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Technical Small cubic inch screamer

Discussion in 'The Hokey Ass Message Board' started by crowman, Jun 12, 2014.

  1. crowman
    Joined: Apr 18, 2011
    Posts: 48

    crowman
    Member

    Can someone tell me what SBC parts are needed to make a 278 or other combination for a small block? I have a GM 3'' stroke 327 steel crank as a start just not sure of the other parts. I want to build a old modified motor. what carbs, cam, pistons ect... Gordon
     
  2. A 327 crank is 3.25 stroke
     
  3. Bearing Burner
    Joined: Mar 2, 2009
    Posts: 937

    Bearing Burner
    Member
    from W. MA

    a 272 is a 265 bored .060 so a 278 must be a 265 bored.080. A 265 bored ,125 is a 283. A 265 is 3 3/4 bore and 3" stroke. You will need a1955-57 265 block
     
  4. pitman
    Joined: May 14, 2006
    Posts: 5,107

    pitman

    Heard a few 301 inch motors years ago, very quick, w/GM parts
     

  5. 1971BB427
    Joined: Mar 6, 2010
    Posts: 7,045

    1971BB427
    Member
    from Oregon

    Never heard of the 278, and not sure what advantages that particular c.i. displacement would give over tried and true sizes. Grumpy Jenkins built a SBC that was around 260 c.I., and a std. 3.50 bore with a 3.0 stroke will get you a high winding 267 c.i. that will wind to 10k rpm if the engine is built right.
     
  6. Harvey29
    Joined: Sep 29, 2010
    Posts: 176

    Harvey29
    Member
    from kansas

    327 crank in a 400 block comes out to a 355 that combo should turn some rpm's

    Posted using the Full Custom H.A.M.B. App!
     
  7. landseaandair
    Joined: Feb 23, 2009
    Posts: 4,474

    landseaandair
    Member
    from phoenix

    Anything under 300 inches seems silly unless rules require it. Would either cost more or be choked off with the tiny bore. 4"+ bore would allow bigger valves and RPMs required to get full potential from the short stroke. Is this going to be a street drag or oval motor?
     
  8. drtrcrV-8
    Joined: Jan 6, 2013
    Posts: 1,497

    drtrcrV-8
    Member

    If you're really determined to go that small, you could start with the 262" v8 from 1975-1976. It had 3.67" bore x 3.10 stroke, but if you wanted smaller, a 3" crank would give 254" ;same with .030 bore would give 258" : with 1.94 x 1.60 heads, roller cam & kit, etc I could see a little "screamer", but you'd better be using all "good parts"(!!!) to make it live! could be 'fun' in a light car with deep gears, not that it's never been done before, but , still "FUN"!! If you 'feel the need' go for it : it's your project, & anyway, it's your 'business" not our's !
     
  9. Anyone ever make a 320 inch by using a 400 block with a 283 crank. Wasn't there a way around the bearing size differences? Seems there would be lots of room for valves.
     
  10. saltflats
    Joined: Aug 14, 2007
    Posts: 10,930

    saltflats
    Member
    from Missouri

    Thats what I was thinking big bore short stroke better breathing room.
     
  11. cambuster
    Joined: Jan 16, 2010
    Posts: 37

    cambuster
    Member

    In New Zealand we have a speedway class that requires 250" max there have been a couple of quick & high revving chevys built using 400 block & short stroke seems to be the way to get good power from small cubes these days as some others have said its the only way to get big valves in.
     
    loudbang likes this.
  12. Leviman
    Joined: Dec 11, 2012
    Posts: 201

    Leviman
    Member

    Build some 180 degree headers for it and confuse the hell out of people. If you could spin it to 9000 you'd have a sbc that sounds like a ferrari.
     
  13. 1971BB427
    Joined: Mar 6, 2010
    Posts: 7,045

    1971BB427
    Member
    from Oregon

    Yes, just going small cubic inches wont get you a high winding engine. Need to think big bore and very short stroke. The advantages of a high winding small block are lost on a street vehicle, and a waste of time and money. Engines that run well at 8-10k are racing engines, as there are few places to be able to drive this type of engine on the street, and they make all their HP at rpm's higher than we would expect to safely drive.
    There's an OT '69 Nova race car that's got a SBC around 267 c.i. in it and plays in the 10k-12k range. Pretty impressive, but not a street car.
     
  14. If you have to ask....
     
  15. Grahamsc
    Joined: May 13, 2014
    Posts: 466

    Grahamsc
    Member
    from Colorado

    IDK if they make them anymore but years ago I hade a set of main brgs that Were roughly 1/4 in thick that were made to put a 327 crank in a 400 block
     
  16. oldgrease
    Joined: Jan 14, 2014
    Posts: 14

    oldgrease
    Member
    from Alabama

    i recently traded for an old dirt track motor. i just tore it down and what they did was took a 350 two bolt block and installed splayed 4 bolt caps and a 327 (3.25 stroke) crank with 5.7" rods and 327 trw pistons(#L2166nf) .125 dome, 10.25:1 comp. the result is a 331ci. i understand it was a real screamer. im going to rebuild and put in a 62 falcon gasser. how this helps ImageUploadedByH.A.M.B.1402674291.725281.jpg ImageUploadedByH.A.M.B.1402674329.575270.jpg ImageUploadedByH.A.M.B.1402674351.917793.jpg


    Posted using the Full Custom H.A.M.B. App!
     
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  17. 69fury
    Joined: Feb 24, 2009
    Posts: 1,419

    69fury
    Member

    Excerpt from a Hot Rod magazine article on Stroking engines: Destroking-
    Keep in mind that the stroking basics shown in this story can also be used to decrease the crank stroke. Why would you want to? Perhaps you run a weight-per-cubic-inch class or a displacement-limited class. Let's say the limit is 305ci. You sure don't want to run a pathetic 305 Chevy, because the cylinder bore is too tiny for decent size valves, and the bore is so close to the valves that airflow is compromised. Instead, use your newfound knowledge to build a small-block with a 4.010 bore and 3.000-inch stroke for 303 ci. Be extra trick and do it in a GM low-deck block (PN 12480050) with an 8.700 deck height to save weight, have a compact size, and keep the pistons short. You could still have 6-inch rods with custom pistons with a 1.200 compression height. With a 2:1 rod ratio, it'd be a 10,000-rpm screamer. Why not?

    Read more: http://www.hotrod.com/howto/hrdp_02...ine/5_ways_to_build_torque.html#ixzz34XYgw4Ba
     
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  18. Wouldn't that be your basic 301 recipe?

    Mega Rpms and gobs of power up there but can't get out if its own way off a stop sign :)
     
  19. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,695

    56sedandelivery
    Member Emeritus

    Just grab a FORD 221 CID V-8 if you want to go small CID, or even a FORD 260. The costs involved to make a SBC that small can't be justified, unless it's being built as a "class motor." Using ANY of the GM, small bore engine blocks is going to seriously limit the valve sizes possible. You could start with a 267 inch SBC, use a large journal 3" stroke crank (either a factory piece or aftermarket, and offset grind the rod journals to small journal size for even less stroke-usually offset grinding is to increase stroke, but it could be done to decrease stroke), aftermarket rods (lots of lengths available), specially made pistons, but the bore of 3.5 inches will limit any larger sized valves being used. Then, to make it all work, high RPM, close ratio manual trans, and L-O-W rear end gears. It'll also have to be a high CR motor to build any power, and then what will you use for fuel? I personally can't see it happening in any realistic fashion. "There's no replacement for displacement". Butch/56sedandelivery.
     
  20. oldolds
    Joined: Oct 18, 2010
    Posts: 3,188

    oldolds
    Member

    Yup, that 331 combo was the way to go at some tracks. If I remember right a lot of tracks set the cube limit so 340 mopar and 350 everything else was not legal. Looks like the right stuff in that one.

     
  21. volvobrynk
    Joined: Jan 30, 2011
    Posts: 3,587

    volvobrynk
    Member
    from Denmark

    This is one way to go, or the very nice combo of the 302 Chevy small block. I Think that some of the guys on here calls it a 301.
    283 block and 327 crank. I belive that 305hipo heads and and a nice cam would make a niece cheap set up.
    Then throw in tri-power/Z-28 carbs and some ramhorns or hedmann headers for the look.
    I Think that with all the work that this takes you can buy a crate motor for the same money.
    But no one would ever mistake your 302 at WOT for a any belly bottom 350 crate motor.

    You car your call!
     
  22. jcmarz
    Joined: Jan 10, 2010
    Posts: 4,633

    jcmarz
    Member
    from Chino, Ca

    this post reminds me of a photo I saw in Hot Rod Deluxe or was it RodnCustom? Anways, it was a few years back and it was just a collection of photos from the 60s and there was this one photo of a mouse motor and the caption read (I can't remember it word for word) that it was a 265 and it turned 11,000 RPMs. It didn't much info as to who built it or how.
     
  23. tommy
    Joined: Mar 3, 2001
    Posts: 14,757

    tommy
    Member Emeritus

    I don't know what combination of parts that he used but I will always remember the sound of a gasser that ran a de-stroked 265. It had to be in excess of 10 grand. I got nervous just sitting in the stands. I kept expecting to see parts come whizzing by. This was in the 60s.
     
  24. Maybe its a typo up there ,,

    283 block and a 327 crank is the "dreaded" 307. The scourge of all SBC engines. :)

    4" bore block (both 327 & 350) with a 3" stroke crank (283) is the "302"- Dz302 z28 recipe with a hot high rpm cam & 301.59 actually.
     
  25. volvobrynk
    Joined: Jan 30, 2011
    Posts: 3,587

    volvobrynk
    Member
    from Denmark


    You are all correct, it's was my falty memory!

    You are correct, the 302 is 327 block and 283 crank.
    The biggest problem with a 307 today would be why borther! Unless ypu have one in stock.

    But I will defenetly do a a 302, z28 cam and all!
     
  26. tommy
    Joined: Mar 3, 2001
    Posts: 14,757

    tommy
    Member Emeritus

    The famous 301 Chevy engine used in the early days of drag racing was a 1/8" over bored 283. If you were around in that time period the old 301 has a special place in your heart. A friend had a 57 283 block (no side motor mount bosses) that he always passed of as just a 301 but strangers did not know it had a stroker crank:rolleyes: WE called them 301s but the newer 302 Z28s rounded up the displacement with the same specs. They will always be 301s to me.
     
    volvobrynk likes this.
  27. That's the way I see it -
    If you built it its a 301 - if its the z28 engine its a DZ 302.
     
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  28. Mr48chev
    Joined: Dec 28, 2007
    Posts: 30,037

    Mr48chev
    ALLIANCE MEMBER

    I'm like some of the others who would have to believe that going with a really small ci Chevy small block would only be productive if you were attempting to fit it in a certain CI racing class.
    In the early 70's you could buy a fitted 302 block over the counter at the Chevy garage once you figured out the parts number. with a 283 Crank and set of rods you had a 302/301 ready for battle. The 283 crank in a 327 block with 302 pistons was popular in the early 70's with The dirt track brigade in Central Texas who ran the modified class at Heart-O-Texas speedway. The guy I worked for back then was the local guru on those engines.

    Want a low buck nostalgic looking engine with plenty of torque. Take one of the disrespected and dirt cheap 307 short blocks, stick a mid 80's Z-28 style cam in it and put power pack heads and a 300 hp 327 intake on it. Looks like a power pack 283 that runs like a bandit. We built one out of left overs for my son's 70 Chevy C-10 in the late 80's that was a terror for city block street racing. That wasn't the intent but the truck built quite a reputation on Yakima Avenue in yakima Wa in the late 80's.
     
  29. Atwater Mike
    Joined: May 31, 2002
    Posts: 10,705

    Atwater Mike
    ALLIANCE MEMBER

    Yeah, Tommy...I could always tell who was around and who wasn't. A 4" 283 was a 301.
    Around San Jose, that was the hot setup.
    Pistons (either J.E. or Jahns?) were also available .060" over, at basement price...so there were some 'street gassers' running 292s. A clique of racers in the San Jose (CA) area were keen on 292s and 301s; Fremont drags hosted the L.A. contingent who were bent on 327s. (1962-1965, thereabouts)
    This was prior to the famous '302' that GM copied from us rodders... LOL
     
    volvobrynk likes this.
  30. there is no good reason to build a small high reving low torque for the streets, but i have one for my altered if i ever get it finished
     

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