I have a 98 baja 302 with 2 of the mercruiser 454 non magnum motors just the standard mpi's. Last year i lost one of the motors, so im in the middle of building a complete new engine since there was pretty much nothing left of the original one, including the originap mercruiser camshaft. I had thought about going ahead and upgrading the cam in the new motor along with doing a cam swap to the engine still in the boat to give a little more power and sound a little better as well. My question is if i get a pair of 454mag cams or the 500hp cams would it run fine without doing any changes to the ecu or how would i correct that without getting into alot of tuning or changing stuff?

The ECM needs to be recalibrated for any cam upgrade.
There is not much to be gained with just a cam swap if you are keeping the peanut port heads.

Did the magnums have diff heads? I was thinking they just had diff intakes,cams, and forged bottom ends

Prob gen 6 vortec scoggins has that cam $225 last time I bought one [/QUOTE]t

330 has peanut port heads. mag has rectangle ports

Change the heads to Dart Iron Eagles and put a hotter cam in. Reprogram on the dyno and you should be at 420+ hp. Go to Bob Madera for the cam.

Wannabe

You would be far better off to just put it back exactly as the remaining motor is. A 7.4 runs it best when it is unmolested. All the internals are cast and the intake runners in the heads are so small...it almost get crowded with a marble in them. If you want to sound better and go faster, then get complete different engines with forged internals or you are probably going to be on the trailer again very soon.

paul,i do believe that is the best advice that could be given!

does anyone know the specs of the stock 7.4 mpi non magnum cam? its a 98 model gen 6 motor with roller camshaft.