94' 454 magnum efi 20ft ski boat
 

Long story short. I cracked a piston and had to tear my engine down. Looks like I need a bore so I'm going .030 over. I think I'm going with .095 dome top pistons because that is the closest I can find. looks like the mercruiser ones are like .120?I searched cams and I keep coming up with .510/.510 220/220 is that a carb lift and duration?? i thought MPI/efi had a high lift shorter duration? Basically I need a cam and pistons so I'm doing a full rebuild. but this is in a ski boat so I need 0-2000 rpms in a useable fashion thanks in advance.
I'll post pics of my carnage as soon as I host them. :)

Where should I get a cam?? What are my options?/ I dont want to recalibrate my ecu if at all possible. I have EMI manifolds and an aftermarket fuel pump/regulator with return system on the boat but thats it for upgrades. also was thinking about roller tip rockers/sportsman style.

I don't think those are the correct specs for the 1994 efi cam. Those are the specs for a carbed 454mag cam. The merc part numbers are different for the 1994 efi and carb cams. The stock cam for your engine is still available from mercruiser for about $250. You can look it up on www.mercruiserparts.com

Maybe rmbuilder will chime in. If anybody knows the specs, he will.

It gives me part number 431-4734 for the cam shaft? But no Specs. My boat is a direct drive with a center mounted engine is it a reverse rotation? I didn't think it was? Anyone? It's a Malibu 1994 Echelon. I would like to get a cam for it if it's available.

I Looked it up it's a standard rotation.. Only correct craft has a R/H rotation prop because the reduction drive turns it around?? Anyone have the specs on the 454 Magnum MPI cam? I can get it cam Dr. checked but It's kinda messed up.

Merc never has the specs except in the repair manual for the engine. If you look at a 1994 carbed 454 mag, you will see it is a different part# for the cam. I know for sure that the carbed specs are .510/.510,.220/.220 on a 115 lob sep. and since yours has a different part number, the specs will be different. I think that cam is still available from GM.

Anyone else out there that might have the specs??? Anyone Anyone.. Bueler bueler. :)