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Puttin' Perfume on a Pig...307 Tech?!

Discussion in 'The Hokey Ass Message Board' started by Fat Hack, Feb 20, 2005.

  1. Fat Hack
    Joined: Nov 30, 2002
    Posts: 7,709

    Fat Hack
    Member
    from Detroit

    INSIDE THE 307 CHEVY....

    It was produced by Chevrolet from 1968 until 1973, and was used in passenger cars and some trucks. They were all two bolt mains blocks and all came from the factory with two barrel carburetors. The 307 was slated from the start as a low performance, economical replacement for the 283, and was never considered a performance engine by Chevrolet.

    Looking at the bore and stroke specifications, you will see that the 307 comes with a 3.875" bore and a 3.25" stroke. What it essentially was, is a 327 crank dropped into a 283 block. No mystery combo there...just an easy to produce base model V8 for Chevy cars using existing parts.

    (So, you can think of your 307 as either a stroked 283, or as a small bore 327!)

    To put into easily read chart form:

    283 = 3.875" bore X 3.00" stroke
    327 = 4.001" bore X 3.25" stroke
    307 = 3.875" bore X 3.25" stroke

    The journal sizes on a 307 are 2.45" for the mains, and 2.10" for the rods. Again, no hidden surprises here, just a common, cast 327 crank in disguise, folks!

    All 307 blocks are two bolt mains, but there are several different casting numbers. One isn't really much better than any other, but I'll list them here for the purpose of aiding in identification, so you can be sure that you do indeed have a 307 on your hands.

    3914636 (1968 passenger car)
    3931174 (1968 truck block)
    3956632 (1969)
    3932371 (1969-1973)
    3932373 (1969-1973)
    3970024 (1969-1973)
    3970020 (1970-1973)

    The blocks are really nothing special. Externally, they look just like any other late 60s to mid 70s small block (400s excluded!), and they accept all such oil pans, accessories, and other bolt-on parts such as manifolds, water pumps, fuel pumps, etc.

    Cylinder heads are a point of concern on 307s. Although they used common castings often shared with the tamer versions of their 327 and 350 cousins, they were saddled with small (1.72") intake valves due to their bore size. The many 307 head castings available are not your best performers, but we can work around that with proper machining and parts selection. More on that later. For now, let's just see what casting numbers were available on factory built 307 engines:

    3911032 (1968, 70cc)
    3917290 (1968, also used on some 327s)
    3917293 (1968, 75cc)
    3931633 (1968-1973)
    3986388 (Used from 1968-1976 on 307 and 350 engines)
    3927185 (1969-1976 307/327/350, 70cc)
    3932454 (1969-1973)
    3927188 (1970, 74cc)
    3986339 (1971 307/350)
    3998991 (1972-1973 307/350, 75cc)
    3998993 (1972-1973 307/350, 75cc)

    As can be determined from the list above, some low performance 327 and 350 engines were also equipped with these small valve heads, so they can be found easily for next to nothing or free, as any serious 327 or 350 build is going to involve discarding those castings in favor of better heads with 1.94 or 2.02 valves.

    In addition, although I didn't list them here, any 283 head castings can be used on 307 blocks. This is good news for those wanting to keep a nostalgic look and flavor about their project, as it allows for the use of the old 283 "Power Pack" heads, and any number of choices from the 283 line-up. This expands your range of selection, and means that you can use 60s style heads with no accessory bolt holes for a cleaner, more traditional look if your 307 build is slated for use in a trad rod or custom. Just more fuel for thought.

    Aside from their bore and stroke numbers, small valve heads, and specific casting numbers, the 307s are just another small block Chevy on the outside, so building one is still a fairly affordable deal. You just have to know what you're dealing with going in.

    BUILDING THE 307...

    307s got a real bad rap early on as poor peformers, and it stuck with them. The primary reason for this awfull reputation, however, comes from one single mistake on General Motors' part...they equipped the 307 with a wimpy, unhardened hydraulic camshaft. These cams wore out very quickly, leaving the engines way down on power and way up on fuel consumption. Many owners failed to diagnose this condition, and just sold their cars in disgust, or swapped in 327 or 350 replacement engines. The fact is, a simple cam swap would have put their wheezing 307 right back in the fight, had they taken the time to check it out!

    So, obviously the first thing you should know about building a 307 is that you're GONNA have to buy a cam. Luckily, there are litterally THOUSANDS of factory and aftermarket grinds to choose from, so fear not, brave warrior!

    The small valve heads, along with the bore/stroke relationship will play a critical role in camsfaht selection. It is easy to "over cam" a 307 and make it perform WORSE if you ignore these factors, so avoid the temptation to use the same lumpity cam your buddy is running in his built-to-the-gills 350! You want a hydraulic cam with sensible duration and relatively small valve lift. This leaves plenty of options open, and it should be said right now that building a 307 for anything other than mild street/strip duty with limited RPM (under 6200) expectations is a foolish affair given it's specific shortcomings. For this reason, we will be looking at cams in this relatively mild range.
     
    Donuts & Peelouts likes this.
  2. Baumi
    Joined: Jan 28, 2003
    Posts: 2,271

    Baumi
    ALLIANCE MEMBER

    Thanks for the good info!
    A friend wants me to build a 307 for him . He had the engine laying around so he decided to use it.
    Your tech came just in time. Thanks!
    Chris
     
  3. Automotive Stud
    Joined: Sep 26, 2004
    Posts: 3,924

    Automotive Stud
    Member

    Sounds good! A few questions I asked myself:
    Out of those stock heads listed, are any worth while, or better then the rest, or are they all hopeless? Are they worth porting and oversized valves or if you get into that are you better off with different stock heads?

    Could it be bored out to 327 specs?
     
  4. Mutt
    Joined: Feb 6, 2003
    Posts: 3,219

    Mutt
    Member

    Why are 400's excluded? Although the early (70-73) came with three freeze plugs, the later ones came with only two.


    Mutt
     
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  5. Hot Rod To Hell
    Joined: Aug 19, 2003
    Posts: 3,032

    Hot Rod To Hell
    Member
    from Flint MI

    Most of the 2 plug 400's had the raised boss for the 3rd plug, it just wasn't drilled.
     
  6. Fat Hack
    Joined: Nov 30, 2002
    Posts: 7,709

    Fat Hack
    Member
    from Detroit

    Correct. That, and the big (externally balanced) dampner and weighted flywheel/flexplate on the 400 provide subtle cues that make their appearance slightly different from their smaller cousins.
     
    Randy D likes this.
  7. Fat Hack
    Joined: Nov 30, 2002
    Posts: 7,709

    Fat Hack
    Member
    from Detroit

    "Could it be bored out to 327 specs?"

    Although SOME machine shops are willing to gamble on this procedure, the cylinder walls of the 307 block are pretty thin. Boring one to a 4.001" diameter is really asking for trouble, but I know of one (now defunct) machine shop that insisted it COULD be done if the 307 block in question sonic checked okay.

    Still, I would NOT advise it. If you want a 307 with a four inch bore...buy a 327!
     
  8. Great stuff Hack! I'll be looking forward to this build.
     
  9. zbadman
    Joined: Jan 31, 2004
    Posts: 4

    zbadman
    Member

    Thanks for the info! It always amazes me that whenever I have a Question on a topic I can find it right here!
     
  10. Mutt
    Joined: Feb 6, 2003
    Posts: 3,219

    Mutt
    Member


    None of which is readily apparent with an installed engine, and few people are even aware of those differences. I wasn't trying to be a nitpicker - but there's been a lot of talk about the differences between small blocks, and externally, there really isn't much that the average joe knows about. Three freeze plugs, no side motor mounts on very early engines, and the road draft tube are the only obvious differences on Gen1 motors. At a glance, the road draft tube is the only one readily obvious on an installed engine.

    If you want a 327, get a 350 block and put the 307 crank in it.

    Mutt
     
    scott27 likes this.
  11. coupe33
    Joined: Nov 23, 2004
    Posts: 590

    coupe33
    Member

    I will just follow along I must have one in the barn someplace. lol
     
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  12. Southfork
    Joined: Dec 15, 2001
    Posts: 1,463

    Southfork
    Member

    Yea, I've got one too! I'll be following this thread closely.
     
  13. DrJ
    Joined: Mar 3, 2001
    Posts: 9,422

    DrJ
    Member

    In my (weird?) way of thinking, putting a 400 crank in a 350 to make a 383 is the same logic as putting a 327 crank in a 283 to make a 307.
    Both end up stroked versions of their original combination, which usually means they will have more torque at the bottom end but be RPM restricted due to not being able to handle big valves for breathing.
    If a 327 or even a 283 is a better combination than a 307 then a 400 or even a 327 is a better combination than a 383.

    But the 383 seems to be the "street rodder's" holy grail?
    If cubic inches is everything, there's no way a 383 can be "better" than a 400, can it?
    (equally "built" that is.)

    The 307 is just a smaller cube version of the 383 formula idea, or the same kind of thinking anyway.
    If the 383 is a "good" idea, so is the 307.

    The bottom end of an engine is basically just a pump.
    The flow of the heads, valves, intake and exhaust are way more important factors, and those parts were all restrictive on the stock 307's so whatever people thought of them in stock form is irrelevant.


    But then, I'm just weird enough to be running a 262 (because the brand new in the GM crate short block was only $400) in my '40 GMC.
    (With World Products S/R 305 heads (1.94 intakes) and a 800 cfm Q-jet)
     
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  14. Upchuck
    Joined: Mar 19, 2004
    Posts: 1,576

    Upchuck
    Member
    from Canada BC

    if them 307 are disgarded as junk then what kind of vehicles did they come in? I'd kind of like to follow this as well and keep an eye out for a cheapo one if it should come along or have an idea what to look for in discarded hulks:)
     
    vtx1800 likes this.
  15. Fat Hack
    Joined: Nov 30, 2002
    Posts: 7,709

    Fat Hack
    Member
    from Detroit

    CRANKING IT UP...

    To keep this tech post rolling, I figured I'd start with the bottom end of a 307 build-up. We know that all the blocks are two bolts, but that won't pose a problem for us, as we're only looking for a good street/strip motor, not an all-out race mill.

    One thing to note, is the crankshaft. All 307s came with cast 'medium journal' cranks, also common to some 327s. The 307 crankshaft casting numbers are as follows:

    3911001
    3911011
    3941174

    The above numbers are cast cranks found in all 307s and some 327s.

    Now, there is ONE 327 forged crank number that has the same journal size (2.45" mains) as the 307, so it is a direct bolt-in for those interested in beefing up the bottom end a bit.

    The 327 forged crank number is 3914672.

    I'm not sure how difficult (or expensive!) these one-off forged offerings are to find, but I will look around for one locally for possible use in my own 307 build-up.

    However, there is nothing wrong with running a cast crank in a moderate street motor, so don't kill yourself looking for that 'trick' 327 crank...so long as your stocker is straight and the journals are clean, it'll be fine.

    While we're on the subject of cranks, I thought I ought to mention bearings. My favorite choice is the famous Clevite 77 offerings available from any decent machine shop, parts place or speed shop. Just be sure to get the proper size (if your crank has been turned) and check the clearances before the final assembly.
     
  16. Regarding DrJ's post about the 383, from the builders I talked to, 400's had thinner cylinder walls and/or smaller water jackets due to the larger bore and were prone to overheating, maybe even cracking? Although I know many people who have had tremendous success with the 400 motor. But if you had a 350 laying around and had a line on a strong 400 crank, wouldn't you want to 383 your 350?
     
  17. overspray
    Joined: Jan 14, 2003
    Posts: 1,232

    overspray
    Member

    Fat Hack, since I'm old and have already played with 307 motors, I'll start of by confirming that you are right on the money. The camshaft was the biggest problem with these motors. The lobes would go flat in a few thousand miles. They were designed to try comply with the up coming emission requirements that the Feds implemented in steps from 1963 to 1975. Most of these motors had an AIR system. This was the Air Injection Reactor or "smog pump" that pumped fresh oxygenated air through tubes in the exhaust manifold to the outboard side of the exhaust port to help complete the burning of the gasses coming out of the cylinder in order to lower the exhaust emissions of unburned hydrocarbons. These little pumps robbed at least 10-12 horsepower from an engine that was also timing retarded due to camshaft design to comply with the emission (smog) laws by extending the time of the combustion process.

    I did 2 motors for myself.

    1-68 Chevelle wagon-307 2bbl with a powerglide. I had some leftovers from some projects for this one. I put in a 350 hp 327 cam (GM #3863151), new lifters, double roller timing set, and a set of 300 hp 327 "camel hump" heads, and a 327 4 bbl intake and Qjet carb and added dual exhaust (no headers).
    MAN--that 307 was a screamer and would smoke the tires off the rims! Gas mileage stayed about the same, but it started and ran soooo much better.

    2-63 Chevy Belair Wagon-1969 307-stock heads (used) with Saginaw 4 speed-3.55 rear axle. This was a beater that we put some "on the cheap" stuff in. The cam was flat in the 307 and I scored a slightly used cam and lifters from a wannabe racer. It was a similar grind to the 350 hp cam I used in the other 307. Put in a new double roller timing set and a stock 63 283 2 bbl intake and carb with some dual exhaust and glass pack mufflers. That set up ran like a top. The gas mileage was better and it was a blast to drive with very good power.

    Another little trick was to use an early (1967 down to 1958) distributor (different mechanical advance), or now days a HEI with an advance curve kit and different vacuum advance for more total timing advance.

    Through the years I had put cams in a number of other 307's-some stock-and my favorite the #3863151 327 350hp hydraulic cam, always with good results. Back in the late 60's early 70's I could buy those cams for about 30-35 bucks. Those were the days.

    I'll be looking forward to your build-up reports.

    overspray
     
  18. Fat Hack, I have almost exactly what you were describing in the 307 block with early 283 "powerpack" heads. It was the original engine in my 38 Chevy when I got it. The 307 was very fresh, and the heads have some port work done on them. Ran real nice, but that was about 8 years ago and i don't recall specifics.

    I will also be following your build-up as this 307 of mine is going to be installed into my 59 El Camino. Paired with a 700R4 and will be my daily driver. I won;t be doing any machine work or taking the engine apart, as it was fresh and clean when removed from my 38. It does look exactly like a 283 with the early heads on it. About the only thing I may do is swap the cam, since I have no idea what is in there now, or for that matter what the compression ratio and the more important cylinder pressure is.
     
  19. Fat Hack
    Joined: Nov 30, 2002
    Posts: 7,709

    Fat Hack
    Member
    from Detroit

    INDUCTION NOTICE FOR THE 307...

    Over the years, I've used many different intakes on small block Chevys, and have come to regard the old factory Z28 aluminum high rise dual plane manifold from the late 60s as one of the absolute best all-around street performance units available. It came stock on the legendary 302 engines, and makes good power up into the 6000rpm range without giving up low end grunt when bolted onto 350 and 305 engines.

    Of course, prices have escalated quite a bit on those old factory intakes since I started playing around with cars over 20 years ago, but luckily, we have other excellent choices available to us today.

    Examining the characteristics of the 307s configuration, we can make a logical conclusion that with it's 3.25" stroke, it will not be the high revving screamer that the 302 is, nor will it have the low end brute torque of a 400. It's bore/stroke ratio favors strong mid-range capabilities, which is exactly what you want. Given that, we can narrow our selection to a select few intake manifolds and go from there.

    Since we're looking for a combination that will run strong in the 2500-6000rpm range, and we know that the old Z28 intake works well in that sort of application, let's concentrate on high rise dual plane intakes set up for a Holley four barrel carburetor.

    Though there are indeed others, the following examples are the ones I feel best suit this particular project, and they are all currently available and affordable choices.

    GM PERFORMANCE PARTS CAST IRON Z28 STYLE, Part # 14096011

    This intake closely resembles the original factory Z28 manifold, but it is cast iron rather than cast aluminum. Normally used in racing classes that specify a cast iron intake manifold, it would do well on this project, or any other similar SBC street/strip application. It's primary drawback is that it is heavier than a comparable aftermarket aluminum unit.

    HOLLEY Z28 STYLE, Part # 300-36

    Holley still sells this near clone of the original Z28 intake, and it's a darn good likeness. It's been a 'secret weapon' of those savvy street heroes who desire the performance gains of the 302 intake without the price tag for years, and still remains a solid choice today.

    OFFENHAUSER 360 EQUA-FLOW, Part # 5693

    These Offy classics have been around forever, and give the basic high rise dual plane design a somewhat nostalgic feel with their timeless style. Decent performers with a bit more traditional vibe than some of the newer offerings.

    EDELBROCK PERFORMER RPM, Part # 7101

    An excellent modern version of the Z28 design from the probably largest aftermarket intake manifold producer in the world. This unit is designed for strong performance right where we want it, and is commonly available at chain stores, speed shops and through mail order outlets everywhere.

    EDELBROCK PERFORMER RPM Q-JET, Part # 7104

    This is essentially the same manifold as the one listed above, except that it features a spread-bore mounting flange for those who desire the strong performance gains of the "RPM" design, but wish to run a Rochester Quadrajet carburetor without using an adapter to do so.

    EDELBROCK PERFORMER RPM AIR GAP, Part # 7501

    This one adds an open area under the plenum to the high rise dual plane configuration, which is designed to keep the incoming air/fuel mixture cooler for a denser charge. Probably one of the best dual plane intakes to date, it would make a great choice for any stout street/strip motor.

    WEIAND STEALTH, Part # 8016

    This one is a favorite among small block Chevy faithfulls who have come to love it's strong performance and relatively trim price tag. It's another example of the proven Z28 design, and is commonly available everywhere, usually for a few dollars less than most competitors, making it an attractive bargain.



    SINGLE PLANES?

    On most healthy small block Chevys in lightweight vehicles, a single plane manifold can work quite well. But, given that the 307 has a shorter stroke than the 400, 350 and 305 variants, it gives up a little bit in the area of piston speed. And, with it's smaller valves...it is far likely to perform better all around with a good high rise dual plane manifold than it would with a single plane offering. I may try an Edelbrock Torker II intake (Part # 5001) on the mill after it's made a few passes with the Performer RPM just for the sake of comparisson, as it DID prove to be the best choice for my 305 build-up years ago, but for now I'm standing behing my decision to run the dual plane intake.

    (The 305 has a smaller bore, but it did have a longer stroke, and it responded well to the Torker II, although some of it's low end grunt was sacrificed for the upper RPM charge. I think that effect would be even MORE noticeable in a 307. The reason I used it on the 305 was because I actually WANTED to soften it's low range torque up some...it was blowing the tires away with the Performer intake (part # 2101), and seemed to be running out of breath at the traps. The Torker II really woke it up at about the 50 foot mark and kept it from smoking the tires too hard off the line.)

    CARBURETOR QUAGMIRE...

    Given the engine's displacement, and factoring in the intake and cam choices (more on the cam later), and also considering the performance goals you may have in mind for this engine combination, I'd go with the Holley 600cfm "Double Pumper" carb (part # 4776) to provide fuel mixing duties on this go-round. The 600cfm vacuum secondaries carb (part # 1850) would make an excellent choice as well, and would improve mileage figures a bit, but I'm going with the double pumper for it's stellar power-making potential, and because mileage isn't a big concern this time.

    MODIFICATIONS???...

    No major mods need to be performed on either the intake manifold or the carb prior to installation. Some guys gasket match their intake runner's ports to the heads, but all I like to do is to run over any rough casting edges or bumps in the runners and plenum area with some emery cloth. You don't want to sand the walls of the runners glass smooth, but you just want to address any odd 'pimples' or stray casting flash that may be in there. Just be sure to wipe the runners clean with a damp rag and blow it out thoroughly prior to installation with compressed air to remove any dust or particles left over from the sanding.

    You can surely bolt your intake on 'out of the box' and it'll be fine, but I got in the habbit of running the emery cloth through 'em years ago, and it just sort of stuck. With some intake designs, I may do a little deft file and sandpaper work to improve flow around sharp edges or chamfer the divider (if so equipped) in the plenum area, but the Performer RPM intake looks pretty clean inside, so only a light 'once over' will be done...just to be sure.

    Between the intake and carb, I'd install an open plenum phenolic spacer to help keep the carb a few degrees cooler, and to slighlty increse the plenum area below the throttle plates for a wee bit more upper rpm power. Aside from that, the intake could well be run "as is".

    The carb can be installed 'out of the box', and simply tuned to the engine once running and after break-in. No milling off the choke air horn or any other such mods are needed. As this will still be a "street" oriented performance mill, the choke should be left functional.

    (Of course, in the tuning stages, jets and power valves, along with discharge nozzles and accelerator pump cams may be changed on the carb to gain optimum power levels, but that is standard procedure with any dialing in process. Initially, though, the carb will be run as delivered from Holley.)

    OTHER OPTIONS...

    By no means should you feel that you can ONLY run a dual plane, single 4v set-up on a 307. If one chooses to step up the power figures some, a tunnel ram could work out with small carbs (Holley 390cfm or 450cfm 4vs most likely).

    Also, tri-power or low rise dual quads (with appropriate carb choices and tuning) are viable options for those of you who may wish to spice up your 307 for duty in a gnarly trad styled hot rod or kustom.
     
  20. zman
    Joined: Apr 2, 2001
    Posts: 16,559

    zman
    Member
    from Garner, NC

    Yep... Had a few, all of them given to me. Cam and a 4-barrel made one of them a damn fine street motor, didn't even pop the heads.

    I'd take one just as well as a 350, chances are the 350 will cost you money, the 307 will be cheap or free...
     
  21. Hackerbilt
    Joined: Aug 13, 2001
    Posts: 6,236

    Hackerbilt
    Member

    Hey Hackmeister...
    What are your thoughts on the OEM steel 4 bbl intakes used up into the early eighties or even more interesting, on the OEM aluminium version used for a couple or three years just before the fuel injection revolution took hold? Both were EGR equipped, but thats easy to factor out...if you don't mind a little block-off plate!

    Current (non-rod) project is getting either an OEM aluminum or a PERFORMER Quadrajet manifold. I'm "leaning" towards using the OEM version...(great way to get it out from under my feet! LOL ) but if the PERFORMER would offer noticable gains, I might be tempted to use it instead.

    GREAT Tech thread as usual man...
     
  22. fab32
    Joined: May 14, 2002
    Posts: 13,988

    fab32
    Member Emeritus

    I've been reading this thread with great interest as I've had my share of 307's over the years. First off I 'd hope that everyone isn't sitting on the edge of their seats waiting for some great revelation from the horsepower gods. It ain't gonna happen. Reality check here: It's a friggen small block Chevrolet and it will respond to ALL of the modifications that small blocks have responded to since the first one was concieved. Granted, quite a few of them suffered from a soft cam problem but so did just about every small block built during this era. The local Chevy dealer replaced just as many cams in 327's during this time as 307's. The problem arose from GM trying a different approach to casting and heat treating their cams in an effort to save some $$$$ and it didn't work. Because the 307 was the base engine in so many vehicles there were thousands sold and consequently thousands that suffered from the "soft cam" syndrome.
    To keep this short so you don't fall asleep I'll stop here and PROMISE to jump back in if I see things getting out of hand.:eek: :rolleyes:
    Just a parting shot. How many of you have heard of Joe Sherman? If you read (and absorb) the recent Engine Masters Challenge that has been going on in Popular Hot Rodding Magazine in recent years and months you may recognize him as the winner of the small block shootout. He's older than dirt and has been building high performance Cheverolet engines for as long as they have been produced. years ago his son was working for him in the engine shop. As with most youngsters he didn't have a lot of money. He gathered up all of the cast off racing parts the went through the shop one summer and threw them in a 307 block. Everything was WRONG, wrong length rods, heads that didn't flow right, a cam that would have been right at home in a pro Stock effort, even mismatched roller rockers that were being discarded. He used a set of pistons that were the right dia. for an overbore but had the wrong deck height. He put in used bearings but did pop for a set of file fit rings that were right for the application. He whittled on the pistons with a Brideport to get the deck height right and tossed the results in a cheap Nova wagon with a 4spd and went drag racing. Result: High nines in the quarter at over 120 MPH.
    So much for the orphan small block. Every engine is an air pump nothing more nothing less. The more air you pump the more power you make, end of story. Oh yea, you've got to mix it with gasolene and start a fire, but there is no mystery to that either. As Lilly Tomblin used to say, "and that's the truth, PPPFFFFFFFFFFFTTTT". Damn, I just realized that there's probably no one here that knows who Lilly Tomblin is. Getting old sure is fun.:rolleyes: :)

    Frank
     
  23. Hackerbilt
    Joined: Aug 13, 2001
    Posts: 6,236

    Hackerbilt
    Member

    Joe Sherman is one of the craftiest SOB's to ever duct tape his window frames in the name of aerodynamics...
    He overlooks NOTHING.
     
  24. re your last statement 327, 350block/307 crank

    this will not equate as the pin to top of piston height is different on the 327 & 350..for the novice...pistons will either come out of the block or will sink back down ...depending on the switch...
     
  25. zman
    Joined: Apr 2, 2001
    Posts: 16,559

    zman
    Member
    from Garner, NC

    If you use the correct piston/rod combo it works fine.... You do know there are different length rods right?
     
  26. Mutt
    Joined: Feb 6, 2003
    Posts: 3,219

    Mutt
    Member

    All you have to do is use a 327 piston. The rods are all 5.7 except for the 400, which is 5.565.



    Mutt
     
  27. leadsled01
    Joined: Nov 19, 2004
    Posts: 1,123

    leadsled01
    Member

    Great thread! 2 years ago I bought a 50 plymouth with a 307 in it.The owner new nothing about it (hated SBC). Anyhow I found the original builder of said car/307 through the HAMB. He installed small cam ,283 heads, redid the valves, installed HEI ignition.. I installed edelbrock RPM manifold 600 cfm carb.Damn thing is unbreakable!! Burnouts and high revs are fine. I tell people its a 307 and they say I'm full of shit. It took me a year to figure out what displacement and what speed parts I had, wish you'd done this thread sooner!
     
  28. krooser
    Joined: Jul 25, 2004
    Posts: 4,585

    krooser
    Member

    I had a '67 C-30 with a worn out 283...redid a 307 w/RV cam, headers, etc. I used this truck to haul my circle track car for two years..survived a 5:14 gear...this engine did all I wanted it to....
     
  29. Rand Man
    Joined: Aug 23, 2004
    Posts: 3,391

    Rand Man
    Member

    Where did you get the info they were made up to 1973? My sister had a '76 Nova and my dad had a'77 full size Chevy. They both had 307's.
     
  30. Mutt
    Joined: Feb 6, 2003
    Posts: 3,219

    Mutt
    Member

    Mortec isn't aware of any after '73. This is from Chevy Performance Vol. 1, a small block book. I'd say you had a couple of rare cars.

    Mutt
     

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