chevy 302

i see that the chev 302s are rated at 290 hp, but i have heard rumors that they were actually around 375-400. Is any of this true??

yes...very much true

But the 302 boss motor will kill it , so i've heard. Not actually bothered to verify it though. And the 351 cleveland kills the 350 4 bolt.

But the 302 boss motor will kill it , so i've heard. Not actually bothered to verify it though. And the 351 cleveland kills the 350 4 bolt.

the z/28 trapped 14.3@101 compared to the 14.5@97 in the boss

Man you people really need to know what you are talking about before you just start shooting things down or saying this will kill this no problem. The boss 302 was a baaaad little motor same with Chevy's 302. The 1970 LT1 was right there with the 351 cleveland. They are pretty much the same. They are the same displacement and very similar designs. Clevelands may have some advantage with their crazy heads.
Back to the original question. Yes, the old 302s from 67-69 were rated from the factory with "290" horsepower. However, it made more like 390hp and with simple mods it could reach 450hp.

I really want to build myself a 302. Is there an aftermarket rotating assmebly to turn a 350 into a 302? That would be one hell of a fun car to drive!

You'd be better off geting a 400 sb.

Well I would also be better off with a 472ci SBC Dart motor. Hell might as well get a 572 or a 632 BBC. It isn't always about displacement, sometimes it is about nostagia. Dont get me wrong I love displacement that is why I have a V8 and I do plan on building up a 400 SBC someday. But I would really like to build a 302 SBC too. A Camaro whose motor that revs to 7k would be pretty exciting to own.

Yes 7K out of a v-8 is nice.

302 (chevy)cubic inches can be had from

283 small journal crank.
327 small journal block
5.7 rod
set of 302 pistons.


You will need a big gear,4 speed or BIG stall to get the power out of this engine. Not really a street engine.

PS 7k can be had out of any SBC.... I turn my 355.. 7200

I know how they were made I was wondering if there were companies out there that would make me a crank to turn my medium journal 350 into a 302.

to answer the question, as i have done alot of research into this, (also search for my thread "new hope for my 302" in this forum) there are no current offerings to make a chevy 302.

the solution is this, get a post 87 350 block. one peice rear main seal, hydrolic roller camshaft equipped and all that. then hit up the junkyards and find a caprice wagon or coupe with the 4.3L LT1 based engine. and get the crank out of it. and also the connecting rods if you want. this crank is the same specs as the original 283/302 crank. 3in stroke, large rod journals, 350 main journals, and a once peice rear main seal. so it will create a modern 302. this is the method i am using for my 302 which i am building. a 99 tahoe 350 block with vortec heads, and the 4.3L LT1 crank.

but i will warn, that the 302 lacked a street following because it was a race motor. low end power was lacking drasticly but in high end rpms they were monsters. Im fully expecting this in my camaro, and wont be dissapointed by some loss of low end power. for others building street driven camaros, a 327, 350, or even 400cid sb would not be a bad idea.

oh and i forgot, the 4.3L crank is cast iron, so it will handle up to 400 safley, i plan on using an extreamly lightweight rotating assembly that will be painstakingly balanced and blueprinted, and ill be pushing it to 450-500hp. if anyone wants a 302, and wants to run say a twin turbo or nitrous injected setup i suggest getting in touch with scat for a custom made crankshaft. the downside, is that they only offer custom billet cranks, not forged, so they cost upwards of 2,000 dollars, the upside, youd have to be one helluva goober to break it.

I am betting you have already thought of this but for my own knowledge, can you take a 283 crank and put it into a 350 with the use of some spacer bearings? Similar to the 377 idea, taking a 400 and putting in a 350 crank?

Would a 307 crank work in a 350? Making a 327 seems to be a little more cost effective then a 302. Could one also put a 350 crank into a 307 block?

ok well i have a buddy that has a fully built 302 in a vega, that car is bad if you are going to build a 302 dont try and use other blocks find one and spend the cash he got his block for $300 and put a lot of cash in it it is now at 750 hp. and this is a camaro forum what is all the talk about fords.

who is talking about fords?????? chevy had its own 302 from 1967 - 1969 offered only in the camaros. It was built by putting the 283cid V8 crank into a 327 block with a 4in bore, creating a 302cid V8, which allowed the camaro to run a sub 305cid V8 in accordance with Trans Am racing regulations. it was rated at 290 hp, but in actuallity made more around 360hp in street trim, and 450hp in racing trim. hence the reason that the camaro owned the trans am circuit in '69.

as far as the hp rating, that is very doable, the reason i am only running 450-500hp, is that my transmission will only handle up to 500hp on a daily basis, im running production Iron heads, and natural asperation, not to mention i am doing all this, and trying to get 30+ mpg out of it. if i could find a guy who could build me a 750hp 5.0L engine that got 30mpg, id be damn impressed and want to shake his hand and buy him a beer.

oh as far as the block choice for a chevy 302, its pretty easy. the block for a 302, 327, and 350 are all the same. so you can choose from any of them. the hard part is the 3in stroke of the 302, which is a 283 crank, so yes, if you can find one, that would work just fine. But they are hard to find, and used ones are always questionable, so thats why i am taking the path of building a new, one peice rear main seal, hydrolic roller cam equipped block 302 rather than a old style two peice rear seal.

What are you going to put the "new 302" into? You going to put it into a 3rd gen or a 1st?

when its finished, its going in my IROC and the L98 is going on an engine stand in the shed.

So are only the Corvette L98 motors equipped with aluminum heads?

yup

If given a choice would you take the iron vortecs or the aluminum L98 heads?

Iron Vortecs all the way, the aluminum heads will alow slightly higher compression, this is worth a few ponys, and higher compression makes better combustion efficiency. however the Iron vortecs have much better flow numbers than the L98 heads which makes far more power. you can do tricks to allow higher compression with iron heads, but you can only hog out ports so far to make up flow numbers. also the vortecs have a far better combustion chamber design, which again makes far better combustion efficiency.

Thought so. The Lingenfelter book I have read he really likes the L98 vette heads, but that is right before the days that vortecs came out. CHP really likes the vortecs but I just like to know what others think. I have been reading a lot about engines and how to build them up but sometimes they conflict with one another and you need a 3rd opinion.

yup, thats why we have forums ;)

I am betting you have already thought of this but for my own knowledge, can you take a 283 crank and put it into a 350 with the use of some spacer bearings? Similar to the 377 idea, taking a 400 and putting in a 350 crank? Hello, You can use a 283 crank in a Large Journal 327 or 350 Block by using special bearings. Available from TRW Part #MS3110P. They are costly, But will do the job. Good luck......

yo man, i havent seen 89iroc&rs on this forum for a whiles.. you gotta stop bringing up the really old stuff..

this is a very informative thread tho, maybe someone should take the info throughout it and make a new sticky.

Hello, You can use a 283 crank in a Large Journal 327 or 350 Block by using special bearings. Available from TRW Part #MS3110P. They are costly, But will do the job. Good luck......
lol, thats two.