70ish

Hi, I have been working to identify and validate all the main parts on my 70 cutlass convertible w/350 4bbl + AC + Cruise. Finally uncovered the head and engine block stamp (under 48 years of crud). Head is 7a which i read is valid on a 70, but the block doesn't match the vin. Block = 32M152712. Vin = 342670M372733. Did the original engines always match in 70 or is it possible that some might not match? If it's not original, does this stamp indicate a different year?

I read thru many posts but couldn't determine if this is a fluke or a non original engine.

Thanks, Ed

Fun71

No, 7A heads are not "valid on a 70". While they will fit and work on a 70 block, they were never installed from the factory. Those are 1972 heads and your block is also a 1972 version. The block VIN derivative always matched the vehicle VIN per federal law. Sounds as if someone did an engine swap sometime over the last 36 years.

The 68 through 72 350 engines were essentially the same, with the main difference being the piston dish volume. The 71-72 engines got very large 23cc dishes to drop the compression ratio to ~8:1 for emissions / gasoline octane reasons. The earlier engines had smaller dishes (6cc for the 10.25:1 4bbl versions and 14cc for the 9:1 2bbl versions) but if you are rebuilding the engine you can put whatever pistons you choose to match your desired application and usage.

joe_padavano

I'm just curious where you read this, since it is obviously incorrect. That should make you question any other info you got from that source.

As noted, the engine was replaced with a 1972 350 motor at some point. VIN derivatives that matched the VIN were required by federal law starting with the 1968 model year. There were no "flukes" from the factory.

70ish

FUN71/Joe_P,
Thank you for the quick reply. I definitely saw the 7A head for '70 in a doc on the internet but it was 1am / a few beers deep and i dont remember which. I will look again and try and uncover it. As for the '72 engine, it kinda sucks. I bought the car when i was 25 in '96 and there was no real Internet then to search info, so i had no idea what i had. 8( Stating that, at least it's not a 442 that would now be worth ~$30k less. 8). The engine NEVER failed to start in all the years (bad battery cable 1x), but it's slightly tapping and a bit tired. I plan to redo the car and might go for greater compressions, but now that this is not the original motor, I might add a mild cam. Maybe EFI. I do want to keep moslty a Rocket and not a Restomod. Also the TH350 and 1 legged diff will keep me power bound (unless i go nuts).

Thanks again.
Ed

P.S. if you know of any reputile restoration shops that know Olds in the North East let me know.