502 or 454 how to tell ?
 

I've come across a ski boat with a big block in it and the owner said he's not sure what the engine is. Is there a way to tell just by looking at it?

Down on the side of the block about in the middle will be 7.4 if it is a 454 or 8.2 if it is a 502.
Eddie

Thanks,I'll check that.
Bill

I looked at the block and no 7.4 or 8.2. It's a gen4 bowtie, in the back corner is 445 high performance. on the right side is the chevy synbol. The owner said it's a 454 and another guy who worked on it 10 years ago said it's a 502. Just looking for some info.
thanks

My gen IV 502 has the bowtie also but that just shows it's a GM performance " bowtie " block i think it could be either a 454 or 502 still . the dealer i got the boat from had it listed as a 454 , got her home stood on my head to see the merc s/n tag to find it was a 502

look for the casting numbers and go here http://www.mortec.com/

this site is an excellent source of info on heads and blocks

BBC numbers http://www.mortec.com/bbc.htm

My 502 is this one

10051107...454...............4-bolt, Bowtie, MkIV, 9.8" deck, siamesed bores, 4.25" semi-finished bores, can be bored to 4.50"

454 has a fuel pump mount and the 502 does not.

The markIV 502 has a fuel pump mount!!

that depends on the engine generation