Street_Machine_302

I really want to build a 302, but these engines are hard to come by . . . . I have heard that I can make a 302 out of a 327 and or a 350 engine. I want to hear form people who have done it and what they found to be a good combination for the engine including block, crank, heads, and cam. I intend to shift out at 8300 rpm.

And is cross ram or tunnel ram more effective?

bombebomb

I do not know your question, but im going to tell you now, there almsot ALL going to say why do you want a 302, id say it, but I can hardly back it up to much. Good luck on your question.

74z28

you make a 302 with a 327 or a 350 block and a 283 crank. I have one right now in my camaro. Everybody says that the bigger the engine is the more potential for horsepower. If you make a 302 be prepared to get some heads that can take being flogged that high up in rpms. It's a fun engine to have though that pulls hard up top. You can also buy a book that has some 302 and 327 engine plans in it.

Wild Willy

The original 302, so I have heard from multiple sources, was a 327 block with a 283 crank, making a "de-stroked" 327- This was to meet a displacement limit in the Can-Am (or was that Trans-Am?) racing series that limited engine size to no more than 305 cubic inches.

Of course, the short stroke meant that these engines could survive high RPM's, people used to run them up to 8000 RPM's or more-

I THINK the factory 302's came with solid lifters, and lots of other performance goodies, too.

Z28SORR

Actually a 327 with a 283 crank is a 301ci. The original 302's, which you pointed out were designed to meet the 5L requirement for TRANS-AM racing, were 350 blocks destroked. I know it's a miner point but the 350 blocks are internally stronger, and so better able to take the stresses of racing. Plus they were all 4 bolt mains.

jg95z28

Actually if you look at the GM production block casting numbers 302, 327 and 350 were essentially all the same block. {1967 all three were either 3892657 or 3903352; 1968 302 only came in 3914678, which was also used on some 327s and 350s; 1969 3932386 or 3932388 or 3956618 or 3970010 were used on DZ-302, LM1 (350/255) and L48 (350/300).} Also 2-bolt and 4-bolt mains used the same block castings in some cases.

They all use a 4-inch bore, only the stroke is different. The 350s were not internally stronger. However, the 302s were. Although the 302 crank was essentially a 283 crank as others have posted, it was a stronger material (hardened crank) and actually carried a different part number. Furthermore, if you ask the Camaro Research Group, they'll tell you in fact they were 327s and not 350s. {link}. A 327 with a 283 crank is in fact a 302, not a 301. But then so is a 350 with a 283 crank. The only difference between a 327 and a 350 is the stroke. (At least if we're talking 67-68 motors here. In 1969 that all changed with the advent of the 307.)

Additionally 1967-68 302s are different motors than 1969 302s (aka DZ). The earlier blocks used small journals, instead of the large journals more common today. (Post 1968.)

http://www.camaros.net is full of 1st gen junkies that can tell you just how to spec out your "own" 302.

FiefSS

I say go for it, if thats what you want. Just be prepared to spend alot of time getting it to run right. But when you rev it past 6,500rpm and it screams sit back and smile. Well... cause 20-30mins later you'll be fixing something but its worth it!

Z28SORR

I suppose this is what I get for being too general. It doesn't really matter what the exact size of the destroked 327's are, NO ONE prior to 67 refered to 327's with 283 cranks as 302's. And I think you'll get some argument on the blocks being the same. Have you ever weighed the small journal 327 against the large journal 350? There is always some over lap when shifting from one engine series to another. I beleave everyone today means the DZ302 when refering to the Z28's not the pre69 engines.
So yes, you are technically correct, but it doesn't serve much purpose as far as this discussion, as it's unlikely that "Street_Machine_302" will run across a pre 69 350 much less an early 327.

markinkc69z

Are you still around?

I have a 302 that I built from a 4" bore block, DZ (large journal) crank, powdered metal 5.94" GMPP rods and some SRP 350 9cc dome pistons.

I have run CNC Victor Jr and Iron Eagle heads on the engine. 1 flat tappet mechanical and 4 solid rollers.

Offenhauser cross ram with a single 4150 top, Holley 300-25 strip domainator, Brodix HVH 1000, BowTie single plane and Professional Products Bowtie clone.

2" primary and 1.875" primary hustler headers.

Aluminum and iron case Super T-10's and a TH350 with 3200 converter.

Results?



The 302 sucks in comparison to a larger engine such as your run of the mill 350 in just about every scenario. The smaller cubic inches are a handicap even if the engine really will rev past 8000, and it will. Tossing the shifter in high gear is disappointing with less than a 4.56 gear.

My hardware wasn't outstanding, but it was at least as good as the good stuff in the early 70's and I think pretty representative of what a hard running 302 was like "back in the day" and that was the point of me building it in the first place.

Its got a ProCharger on it now which totally changes its character of course.

Do yourself a favor and ignore the nostalgia and myths, a 350 will be more satisfying and more capable.

CID= bore x bore x stroke x .7854 x cylinder count

4 x 4 x 3 x .7854 x 8 = 301.59 or 302 cu in for those of you confused

same as a ford 302 or pontiac 301

Street_Machine_302

So, I am reading a book on chevy high performance valvetrain and I figure regardless the engine I build I will probably need a solid rocker shaft system. I intend to run stock or vortech heads and want to know weather crane or comp make the solid rocker shafter for these heads and how much this is going to cost. I really like high RPM engines and I am looking for power but the car I am putting this in weighs 2800 lb with me in it.

I heard you guys loud and clear the 350 seems to do the high rpm and give more usable power because it can deliver down low as well, but I still want a high reving engine regardless 302 or 350. So I will be paying attention to what you gentelmen suggest for the valvetrain.

Thank you, Street_Machine_302

jdl79

Hi, I'm new here. I'm sure this thread is probably old but want to share some info on the subject of the 302. The 302, according to Chevrolet, had the 4 inch bore of the 327 and the 3inch stroke of the 283.... engines according to Chevrolet in order of manufacture dates: 283 has; 3.875 bore,3.000 stroke. 327 has; 4.000 bore, 3.250 stroke. 302 has; 4.000 bore, 3.000 stroke. 307 has; 3.875 bore, 3.250 stroke. 350 has; 4.000 bore, 3.480 stroke. Not trying to step on anyones toes but this is straight from the horses mouth via Cranes Corvettes who manufactures new 4 bolt standard bore vintage blocks for all year Vettes. This may be irrellavent but it's what I know. 302's are freaking awsome engines and can produce a ton of upper end HP if you feed it right, but the only reason you need one is for going around a track instead of street racing or strips. It was designed for corners and thats what it's good for...Actually, awsome for. But if your just toolin on the street or stip, my suggestion is a 350/355, or if ya want to spend the money, do it right and build a D-377.