How to ID a 502 from a 454
 

Besides the engine ID tag how can an 502 be Identified? If it's block numbers where do I need to look and for what?

thanks

If the motor is apart look for the Siamese cylinders, larger bore, numbers should be on the block in front of the right head. Might have 8.2 instead of 7.4 on the side.

list the casting numbers nearest to the bell housing area and i will tell you what you have.

7.4 or 8.2 right on side of block near motor mount boss

Thanks and will get numbers over the next few days...

Engine block numbers ID as HJ and according to google it's a 502MAG EFI. Also looking for repair manuals, not just the service manual but more in depth for EFI diag and engine repairs. Not that I will need anytime soon but want to be technical informed. My Engine number is 0K173320... my preference is Mercury OEM not unless sometime is just as good offered

Not to sure about the HJ, I would look below the distributor on rear deck of the block for numbers like found here

Mortec Chevy V8 Big Block Casting Numbers

MK IV 8.2 Litre have Chevy Bowtie just above the oil pan in front of the starter on the stbd side. The Gen 5/6 blocks have a "8.2" cast under the engine mount opposed to 7.4. Gen 5 blocks (non roller cam) have steel timing cover opposed to Gen 6 with aluminum.