Marinette Boat Forum

I have been kicking tires considering the purchase of a 28' Marinette Sportsman with twin 318's. Before I go whole hog, I wanted to ask about the reverse rotation engine.

Are there reverse rotation cams available? Is the rotation of the distributor backwards as well? The gear on the back of the cam that spins the intermediate shaft- is it cut in a reverse pattern or is it the same pattern as a regular small block?

Since I will be building motors I would love to be able to update both to magnums with the roller cam and need to know the answers to these questions to see if I can have a cam ground for my application.

I have build a lot of these small blocks and have even retrofitted an OBD1 magnum motor into an older vehicle. I think it would be cool to do the same with these boat motors. Has anyone tried this swap?

If I can't get the roller cam I want I will at least use some magnum style heads on the rebuilds to get a good quench motor.

The Chrysler Marine pats manual lists separate part numbers for both the cams and the cranks. The distributors turn in opposite directions as well. Some of the Chrysler Marine vendors carry reprint parts catalogs. Get one and you can see all the CW and CCW part numbers. I have gone thru my parts manual and crossed just about everything to new, easily accessible parts/numbers. The only things I can't find cross references for are the backwards cam & crank.

I get my cams through Summit racing
Melling
Std. Rotation p/n 23103
Reverse rot. P/n 23104
Still readily available.
The only difference I have found in cranks is the direction of hatch marks where the seal rides.

I do believe that the distributors both turn the same direction, but it wouldn't be the first time I was wrong.

Distributors both turn same direction. That is why they have the thrust spacer and different driven gear/oil pump shaft.

Thanks EWRice for the info on the camshafts. That's one less item M owners have to worry about trying to find !

Thank you to everyone for your help. After I make my purchase I will be around these parts quite a bit as I plan on doing a full restoration.

Welcome aboard!

Jeff