Difference between 454 and 502
 

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.

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

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

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

But maybe its a 454 stroked to a 502 ?!

Where might that tag be located

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.

blocks
 

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

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=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.

yes this is a mercruiser bone stock

Usually all of the merc motors would have a name on the air cleaner or motor cover. If none of this than pull the serial from the block or tag and look it up.

Thanks for the help guys