454 and 502 form and fit
 

Are the 454 and 502 Blocks the same? Can I use a 502 as a direct replacement?

Also, my 454 is a 1989. Can I use the exhaust, sea pump, alternator and power steering brackets on a 502.

I need to replace the engine and I need to know my options.

Not looking for outrageous horsepower, just want reliability.

Scott

If they are the same Gen blocks, then yes.... If going from a gen 4 to a gen 5, I found you have to drill out some accessory holes to allow for the larger tapped holes in the newer gen block... that should be it really. I went from gen 4 454's to gen 5 502's and that is all we had to do.

Depends on the block. I went from a Mark IV 454 to a Gen 6 502 and had to buy new sea water pumps and brackets/assemblies, fuel pumps (I went the sea water pump mounted route), and flywheel. We also had to buy a oil filter adapter (canton racing).

I've got an extra sea water pump bracket I'm trying to sell if you want it. http://www.mercruiserparts.com/Show_...SEA+WATER+PUMP #25. I'll sell for $100 OBO, $360 new