Hello everyone.

I'm reassembling my father's 3.0s, and in the process I've deemed the engine block dead and gone. The wrist pin has literally killed the third cylinder with 2-3mm scrapings on each side of the cylinder.
So I need a new engine block, and I've stumbled upon a 3,5L block form a 635i from '81. As far as I can tell, heads and blocks from all M30 generations are - with exceptions - interchangeable.
What do you think about this constellation? A '73 head from a carbureted engine matched with an '81 3.5L block? The only obvious difference i've spotted is teensy small cooling canals in the engine block that aren't there on the original 3.0 one. Is it just a question of using the correct head gasket?
I've read an FAQ at firstfives.org about the interchangeability, but would like to know if anyone has first hand experience or intelligent opinions about the match.

All comments would be appreciated.