nwjetter

Hey,
I know this motor may not be going in a boat like most of yours since ours is a 18' jet boat.... but i see plenty of you with some big healthy and sometimes CRAZY motors so ill see if you can help.

I’ve been looking at the 502 short block that is offered by Scoggin Dickey Chevrolet in their catalog.It’s a generation VI 4-bolt block with a forged crank, 7/16 rods and forged pistons and roller cam. The catalog says that with a 119cc set of heads I would have approx. 8.75-1 compression ratio.

At the same time I have a fresh rebuilt set of Mark IV 049 heads with CompCams 924-16 springs along with a Performer RPM manifold and a 800 Holley. From what I’ve been told and seen in books these heads should fit but I wanted to run it by you first.

The reason I ask this is because I have posted this very same question on the Hotboat forums and came up with a mixed answer. Some said that these heads will not fit on the genVI block.They say that the mark IV head have different cooling passages then the gen VI block. But others said they would work just fine. Just looking for another opinion because i dont want to buy this 502 short block if our heads wont fit up!!
Thank you very much, Ian

rpcrack

The MarkIV heads will work with the Mark VI block, not the Mark V. You must Use The Mark IV head gaskets.

Mr Gadgets

rpcrack is correct. I have a gen V and the holes on the deck are shaped funny and without special adapters and gaskets the genIV heads wont fit. I had merlin iron heads and then Dart aluminum heads and they were not a problem. They fixed that mistake on the Gen VI block.

Good luck..