Can you build a real Chevy 302?

Funny, I'm getting ready to build a motor like you described, but bigger holes. We were just planning it at the machine shop yesterday. 400 Block/ 4.158 bore, 350 crank offset ground with 6.125 rods.

 

I cant believe no one's responded....

 

ha ha... busted... sorry I'm confusing my SBC stuff... that's how you build a large journal 327... and cheap to boot....

 

well, as far as 9k rpm, i can honestly say my 292 (283+060) went 8K regularly and yeah,it had deep gears...but it wasn't in a 'pala, (210 56 chevy)

 

Has anyone used bearing spacers to put a small journal sized crank in a large journal block?

 

Pistons are hard to get for the 302. My buddy has one in a 67 Camaro. He bought a genuine DZ block and a 302 crank years ago when you could still get them new over the counter. 20 years latter when he was ready to rebuild it he called all the big piston suppliers and couldn't get a set anywhere. He finely decided 6 of the old pistons were still serviceable and called all over for the other 2. Got one from a warehouse on the coast [the only one they had] and one from a racing engine builder who had one left-over on the shelf. I'd say unless you have Egge make you up a set its going to be tough to do. But man will they RUN! My buddy's rebuild dynoed at 335 HP with no time to do any dyno tuning. Theres plenty more power in it.

P.S. Uh, got some updated information last night from my buddy with the 302. He says Ross now makes these pistons again so they should be easier to get.

 

The Z28 used "pink rods" and they had as follows:
302 (Z/28>

• small journal, 11/32 rod bolts in 1967
• large journal, 3/8 rod bolts 1968, 1969
• forged steel
• shot peened
• heat treated
• magnafluxed (known as "pink rods" due to the pink residue)
• babbit dipped
• 1967 - early 1968 pressed pin
• late 1968 - 1969 floating pin

The outside company I was referring to was apparently Winters for the intake. Several others, notably Offenhauser and Edelbrock, copied the designs of both the hi-rise and dual cross ram. I guess I confused design and manufacture but Chevrolet didn't cast them in-house.

 

There was one on FordBarn the other day......for sale........NOS in the box with 1969 bill of sale from the GM dealer paperwork for 5 grand......

 

used spacers to put a 350 crank in a 400 block, bu ti had alot of money in machine work. use a good shop, stud everthing you can, let them align everything, no problems

 

As with the early 283s being forged cranks, so early blocks were thicker. Strength had less to do with either than technology. Casting technology wasn't up to producing a crank that would last under moderate abuse until the early sixties (63 or so). So engines produced before then all have forged cranks and rods, and the cylinder walls are around 1/4" thick (sometimes more like 5/16"-3/8" at the thickest part -- remember core shift?). The iron is as strong in the blocks, they just couldn't cast it thin and not have hard spots and such that would flaw the casting. May have had as much to do with making the molds as pouring hte metal, I'm not sure on that. But that's why a "little" 1957 195.6 cid Rambler engine weighs as much as a 1980s Ford 302 small block, and can be bored 1/8" easily. The Rambler engine also has forged crank and rods, so materially is stronger than the 302! I wouldn't want to sling those long (around 6.5" -- or more!) Rambler rods around at high rpm though!


Chevy made the 302 specifically for Trans-Am racing. T-A rules limited cars to a 5.0L (305.12 cid) capacity. Ford was running a 302, Chrysler was running a 303 (destroked 340), and AMC ran a 304 (a destroked 360 block, not a standard 304!). The 302 Chevy was the easiest way to get max displacement at cheapest cost and still have a strong contender.

 

That's what we're building for the salter.
No magic dust. But ifin' you want it to rev and live you have to build your lower end right. none of this i'll just slap it together with everyones discarded mismatched parts. IE 6 cast pistons from joe bonjonski and a couple of forged ones from sarah whittlesy's second cousins uncles first boy friend after he went on the downlow. and then half a set of used main bearings and a new one of a different tolerance etc.

You catch my drift right?

 

We were trying different combinations because of the resources that were at hand. This was in 1986, and the shop was known for their "trans am" spec motors of the time. They also built motors for the now IMSA racing series, and wanted to see what I could get out of the 2.02 heads I wanted to run. We ended up with a 12.5-1 compression ratio, with ported 2.02 heads, and an Edelbrock "tarantula" manifold. This gave me a high rpm redline, and gobs of low end tourque. We also tried Brodix heads, chevy bow tie heads, etc.. Oh, and we also settled on pink rods (lightened and balanced). This was one of my first major builds, and I was doing as I was told because I was learning a lot along the way. Yes, this was not the most efficient way of building a motor, but if you had the opportuninty to build a motor along side some REAL race motor builders, and at no charge to me, I am sure you would also take the time to learn all you could. Every combination was a learning experience. I learned how to tune on a dyno, and I learned what I really like in a motor (power curve, usable power,etc..)
And ironicly, the Nova was baby shit brown primer, with a muncie rock crusher, and no trim. Made for street racing. (as stated by someone else above.)..

 

Have ya'll seen the new hot rod? A guy from near Atlanta here won the dream motor contest - his dream motor was a 302 screamer. They have the total build on it. tghey may 400HP or TQ at 7K on the dyno. Nice motor. The article gives you all the parts and specs. Just what we are talking about here. Pretty cool.

 

TRACO built the actual T-A race engines for Chevy. They also built the AMC engines, with some input from Mark Donohue and Penske. None of the engines were factory built or "off the shelf". They were required to use factory available parts though. In order to use the parts, there had to be documented proof at least 100 of them (or 100 sets in the case of things like rods) had been used in production vehicles prior to 1970. The easiest way was to make a "T-A Special Edition" car. Beginning in January 1970 the rule was changed to a percentage of the production of the model (in the previous year) the part was to be used on, unless the part was a documented regular production part. I don't know what the percentage was (something like 10-15%?), but there had to be 1501 Donohue Javelins built in order to use the "duck tail" spoiler Donohue designed for the T-A Javelin. AMC got his signature on the spoiler by saying that's the only way they'd go to the expense of building enough cars with it for him to use -- they wanted the more or less "guaranteed" pay-back by using his sig free of charge! Sonohue wanted the spoiler, so agreed.

AMC got around having to use the special heavy casting block by making it a "service replacement" item. The AMC 390 and 401 engines have thicker main webs than smaller displacement AMC V-8s. Donohue wanted that and thicker cylinder walls. AMC cast the service replacement block and made it a standard replacement part. It's a 401 mold with 360 cylinder cores (0.085" less bore, or thicker walls). It can be identified by having no CID cast in the side, but the 401 casting number. In theory the block was used to replace damages blocks that still had useable internal parts. Because of the bore and cylinder wall thickness it could be used to replace any 343/360/390/401 block. Only a few have turned up as verified dealer or factory replacements, many were ordered to use for racing. But it didn't have to be used in the Donohue edition Javelin, which could be ordered with a regular production 360 or 401.

 

Look in the latest Hot Rod issue they did a build up on one.

Just need a 283 crank with a small journal 327 block. The early Z28's were 2 bolt motors and were not 4 bolts until late 68 and into 69.

 

I raced with 2 bolt main engines for years, I always used ARP bottom end studs and ran taps into all bolt holes so bolts or studs do not bottom out on crap or give false torque readings.

 

This is one mill i will build someday myself. I'm a BIG fan of the small journal sbc's..
I know of a guy who has a brand new (N.O.S) '69 302 still in the GM crate.
it was purchased over the counter as a replacement mill for a guy who blew his Z-28 up, but ended up selling the car and kept the motor..
He eventually sold it to the guy i know..
It has the DZ code, but rather than having a serial number as they normally would it has a service number on it along with another letter or two denoting it as a "service replacement"..
He has no car to use it in, and won't sell it..
Makes no sence....


Thanks for all the good info here!!
Tony

 

What month is the Hot Rod magazine that the article is in? I get that mag and don't remember seeing it. What's on the cover?

 

I hate to re-light the fire on his one, but anyone have any info on building a newer style 302 Chevy motor??? I read the article in the '90's of assembling a 302 using the new (90's era) L-T1 block and L-99 crankshaft. The motor ended up in a black '68 Camaro and I'm not sure which magazine the article was printed. Back then, I was working for Batten Performance machining some L-98 and LT-4 Vette heads............. Thanks in advance!!

 

I found a GM catalog with intake numbers for the 302. The single carb manifold set up for a 850 Holley was # 3958627. The staggered dual quad for two 600 double pumper Holleys was # 3940077. The dirt modified I wrenched on back in the early 70's had a 302 with the off road chevy cam 12:1 forged pistons fuel injection 2.02 heads tunnel ram intake with a big Holley set up for alky, and a Vertex mag.. It won many features on short tracks, It was so loud it pounded your chest when you were next to it. Man those were the days!

 

I've heard the easy way (per a crank grinder) is to take a 350 crank, turn it down to the 283 journal sizes and go play. Sounds o.k. to me, the 350 crank has a lot of meat and is laterally stronger than most other Chevy's.
FYI
cooger

 

A good friend of mine is building one for me, that I will put in a Off Topic ( for this board by about 8 years ) Euro Street & Roadrace car.

I'm sure it will seem wrong to the Z28 restorers.

But it would have been exactly the thing that racers would have done for Racecar Classes like the NZ All Comers, the UK Super Saloons, etc...
( and maybe Mulholland )

If you look through my Albums, you'll find a couple of pics of it.

 

the one that was in my dragster was a 283 bored to 4'', and the steel crank from a 283. I have a extra crank that came from Smokeys stash. it has paper work that it was his. I shifted mine a 8k and it is still in fine shape. just built another s/j eng 327/.030/331 used alum rods this time.

 

Put a 262 crank in a 350 block. Large journal. (Smog motor, 3.10 stroke 1975-1976)

It comes up 312 cubic inches, not sure about what rods and such to use.

Or use the 79-82 267 with a 3.50 bore, with a 3.10 262 crank, and build a 239 for no reason at all.

 

i dunno if it was brought up, but mine is a 350 block with bearing spacers and 283 crank, race engineering makes the spacers

 

A 302 Chevy is what i've been wanting to build for years ....thanks alot guys this is alot of help!

 

LUCKY...7000 R.P.M. hell brother that's pissant revs. for a chevy. mill. in 1964 i left the line at 6000 r.p.m. and jazzed that 327 up to 10,000 r.p.m. at the finish...that's why i say S.B.C. RULE!...POP.

 

From what I understand 62 and later 283 blocks are best to bore to 4 inches.
Most early 283 cranks are forged
Two bolt main blocks are fine and in fact 4 bolt blocks tend ro crack in the web area where the outer main bolts go.
I would only use a 301/302 in a light car
These engines will twist past 7K
I would rather run an early 2 bolt small journal sbc than a later 4 bolt large journal.

I have a factory 302 replacment engine that I am just waiting to find the right car to put it in.

 

Uh..... ALL 327 blocks 1962 and newer are a 4" bore already.

 

DUH I ment 283 blocks I understand that the early 283 blocks 57 -61 may be to thin to bore 125 over But still should sonic check.