Hey everyone, I just found a 4 bolt main core for a decent price. I just looked up the casting numbers and it's apparently a 302 block from a 60s camaro (3970010) from my understanding the only difference between the two engines was the crank and stroke.. so that being said, if I got the 302 block and put a 350 crank with a 3.48" stroke it would be a 350, right? Tia! Wanting to do a 350 build and I think this block is a good start to a budget build.

 

Been a while since I brushed up on my Chevy ID numbers but if I recall there can more than just block number to identify them. For example that block number could have been used across many platforms, but may have stamps like “DZ” to designate it was a 302 Z-28 for instance. Years ago I thought I had stumbled upon a 302 engine based on some block numbers I found and researched. In the end, it was a plain old 327.

 

3970010 is probably the single most common 4" bore block made. It was in 302, 327, & 350 from 69 to 79 or 80. Miraculously, somehow every single one that somebody randomly comes up with, whether from a truck (very common), an Impala 2-bbl (even more common) or WHATEVER, magically and automatically becomes a "69 302" or "70 LT-1". Which is more or less irrelevant anyway; a block is a block is a block is a block is a block as far as any of that goes, once you take the guts out of it. You can take the lowliest 350 2-bbl block and turn it into a 750 HP race motor, or take a "LT-1" block and turn it into a 160 HP smogger turd, according to what heads, cam, pistons, etc. you put into it.

Yes you can put a 3.48" crank in it, and of course pistons with the right deck height, and turn it into a 350. Since of course that's what all those 70s 350s that GM built with that casting # had in them.

In 2020, I would NOT use a 70s block, ANY 70s block no matter how romantic some of the applications of its casting # might sound, as the starting point for ANY kind of build, other than a "numbers matching" deal. Which if that's REALLY one of the last 3 302 blocks with the right FACTORY stamping #s on it for a 302 still left in the wild, some early Z28 person would SNAP IT UP at a high enough price to buy several dozen FAR BETTER (roller cam, modern quality control) 350 blocks.

In short, not a great idea.

 

Incidentally, post up the casting date.



It's 4 characters (1 letter, 3 numbers) in that raised obround feature just to the right of the cyan rectangle around the casting # in the pic.

 

Yeah, just in case it's actually one of the few blocks that's worth anything.. actually theres a set of numbers stamped onto the head surface of the front passenger side of the block that tells more.

I agree, a later roller cam 1 piece rear main seal block is much more desirable these days to build a motor from.

 

Yeah if it's worth something, SELL IT.

Casting date would have to end in 8 or 9 for that. And the stamping code would have to end in DZ.

If it's like the other 99.99999% of 010 blocks, sell it anyway; let it pass on to The Greater Fool; and buy something decent.

 

If the 302 would have been so great they would have stayed with it... but they didnt. They made hundreds of thousands 350s for a reason.

 

They did not make the 302 because it was "better than" the 350, which came out the same year (67) in the same car line, as the Camaro SS. (not the SS396 which obviously was something different) They made the 302 because SCCA had a 5.0 liter limit at that time on the Trans Am series (which Pontiac DID NOT run at the time, they just BOUGHT the use of the name) and GM had to produce 500 copies of it MINIMUM ("homologues") and make them available for sale at dealers. In 67, the 302 was small-journal, and they just did what hot-rodders had been doing for several years by then: take a 327 block and put a 283 crank in it. Some 283s, you could bore to 4", even; before the 327 was introduced. Which is where it got started, it was called a "301" back then. It wasn't because the 302 was "good" in the sense of, it was The Best, and there was No Better Option; rather, it was because it was AS FAR AS THEY COULD GO and still participate in that particular class.

We all knew within a few months of its introduction, that you could walk into the stealership and order RPO "Z28" and you would get basically a race car. That was the first RPO code I know of that made it out of the factory and into the general public's lingo; long before ZL1, L anything, Z71, etc. Solid cam, Holley carb, 4-speed, 3.73 gears. You couldn't even get A RADIO in a car with that RPO. I think the ONLY creature-comfort option available was a heater. They were SO OVERWHELMED by the demand that in 69 they expanded what you could get because people wanted to order THAT plus AC, FM radio, vinyl top, disappearing headlights (the RS package), carpet instead of a rubber mat, etc. etc. etc. Automatic transmission came still later. Oh yeah, those were the daze.

The SCCA eventually changed their rules and after that even Pontiac could participate.

 

You'd do well to pass on that ancient block and instead, start with something newer---one provisioned for a roller cam and with a 1-piece rear main seal.

But as these-type threads almost always go on this site, you're gonna disregard this advice and use that old block anyway. So be certain that the first thing the machine shop does after it comes out of the hot tank is check it for cracks and for core shift before you have any machine work done on it.

GL with your build.

 

If my reading memory serves me correctly Pontiac also had to pay SCCA $5 for each car it sold using the Trans Am name. That was probably a lot back then lol