blackta

What is the easiest way to tell the difference beteween a 502 and 454 when in the boat. Looking at a boat that is supposed to have a 502 but not sure and want to check it out tonight

FIXX

Casting numbers on the back of the block is the best way to tell..

also i dint know if they all had this but mine have a 8.2 casted on the side of the block next to the freeze plugs.

blackta

Do you know what the casting number should be for a 92

1BIGJIM

There should also be a metal tag attached to the block with the serial number on it.

DareDevil

454 has 7.4 on the side of block
502 has 8.2 on it !!!!!

But maybe its a 454 stroked to a 502 ?!

blackta

Where might that tag be located

GTOFFSHORE

On the back by the bellhousing but usually doesnt survive that long. Is a mercruiser engine or a custom. A merc motor will have it on it or at least you can look it up. Other than that you will have to pull the casting number and look it up.

bcfountain

i may be wrong but i thought 502,s had no provision for a mechancal fuel pump,no casting for it on the block.

kreed

Gen 4 502's have a mechanical fuel pump on the block. Gen 4 502's also have a chevy bowtie on one side of the block....hense, a Bowtie block! Gen 5 and 6 blocks need to run electric fuel pump or off the sea pump.

apollard

[QUOTE=kreed;3189572]Gen 4 502's have a mechanical fuel pump on the block. Gen 4 502's also have a chevy bowtie on one side of the block....hense, a Bowtie block! Gen 5 and 6 blocks need to run electric fuel pump or off the sea pump.[/QUOTE

Gen 5 454/7.4 also do not have the casting for block mounted fuel pump. At least my 7.4 doesn't.