Late 512 blocks
 

I have 2 4 bolt main big block with casting date of j10-9 and L 9-9. One was decked and has no # but an assembly date of 10/9/69 the other is a CE stamping. Would these be 427's or 454 block? Any help would be appreciated. Thanks

Re: Late 512 blocks
 

I believe they would be 454 blocks but 427 stuff would work in either one.
James

Re: Late 512 blocks
 

It is possible, although unlikely, that the J-10 block is for a COPO. I'd check the rough area adjacent to the oil filter, in hopes of finding a Camaro VIN there. I don't know the latest known COPO block date, but it's worth a look.

Re: Late 512 blocks
 

When viewing the cylinder case (engine block) from the bottom, if the cylinder bores have large reliefs at the bottom, that engine case (block) was designed for a 454. Those reliefs are for clearance with the quarter inch longer stroke crankshaft used in 454 applications.

Re: Late 512 blocks
 

512's. If the casting date is on the side it is a 427. If it is on the rear it is a 454.

Re: Late 512 blocks
 

Why would they cast the 512-blocks with different date-locations in late 1969, when 427 COPO-engines and 454 LS6-engines where built at the same time ?
I have a pic of the back of my friends 427 COPO-engine, and even though there is much paint on it, I´m sure the date is there. Car was built in early July.

https://www.yenko.net/ubbthreads/imag...s/confused.gif

Re: Late 512 blocks
 

Here is a 512 block, casting date 22 April -69.
Didn't they make L88,L72,L71,L89 Crate engines late -69?

http://farm4.static.flickr.com/3328/...531511a0_b.jpg

Re: Late 512 blocks
 

427's with the casting date on the rear will have the notches in the block for the 454 crank clearance.

Re: Late 512 blocks
 

I've had two 512 blocks with the casting date on the back. Both had the reliefs for the larger crank. One was a 2 bolt LE 69 Impala motor(forget the date). The other is a June 69 4 bolt CE motor.