Looking for some experienced input re the following -

Replacing one of the carbureted 496s in my 1989 boat (bored and stroked 454s). The casting number on these blocks is 14015445 - used in light duty trucks 1975 through 1987, and obviously held over on the marine side through 1989.

Have located a 454 casting number 361959 which the owner says is a 4 bolt main engine out of a 1980 truck.

Anyone know if these two blocks are identical as I want to bore/stroke to 496 using my forged crank and pistons, and swap on the ported rectangle heads etc? All the parts are good to go as the problem is a cracked block due to ingested mud hindering the drainage last fall.

I presume engine mounting points are common on both as well?

Thanks in advance.

Gord