Identifying 502's
 

Does anyone know what the stock carb'd 502's in a 1992 fountain 32 fever are rated at, HP wise? I cant seem to find the specs listed for engine options to find HP, generation, etc.

Thanks.

I believe it's a 425 crank... 390 prop if it's carb... 415 prop if it's fuel injected.

390 hp

Everything inside them is the same as carbed 454mag/365hp

Thanks!

92's I believe are all Mark IV blocks. I know mine are Mark IV, mine are also bowtie blocks. Some were standard 4 bolt blocks and some were bowtie. From what I've read when Merc first started using the 502, GM ran out of standard blocks so to keep production going GM would use bowtie blocks.

the early 502s were bowtie blocks,i believe they used a gen 5 block starting in 92 but not sure.

Is there a general consensus on which block is better? If so, how do you identify either block. I know nothing about engines other than the very basics.

bowtie blocks will have the cheby bowtie cast into it, I think the bowtie block has more material in the piston wall area to go bigger bore size

I dont think there ever was a MARK IV 502 NON bowtie block. Production 502 blocks, started as GEN V. I think mercury marine was one of GM's biggest customers with a demand for a 502ci block, and they went into the mass production process of them. The bowtie mark IV's were used from around 1990-1992. 93-95, was mostly gen v production blocks.

The Mark IV bowtie, is a much better block than the GEN V production block. If it has a fuel pump boss, and a bowtie emblem cast into the side of the block, its a Mark IV bowtie. No fuel pump boss, prob a GEN V production block.

IS your fuel pump on the block, or on the sea pump?

If memory serves, the mk iv bow tie blocks were available as standard or Siamese bore. The Siamese could take a larger bore. The block id number will also identify it.