Could any tell me if the 350MPI motors have good parts? Is the crank steel or cast,and if they have forged or cast pistons? thanks. Happy Holiday

Only thing different about the 350 MAG over the other 5.7's is fuel delivery. Everything else internal is the same.

From what I've heard, they are good for up to the 450 HP range.

To the best of my knowledge, Merc has not changed their thinking on the 350Mag since its introduction in late '86 early '87.

All of the Mag engines still receive forged cranks and pistons (all the SBC rods were forged). This is based on the 4-bolt main block. The lesser models 5.7 and 5.0 get the same components that were used in their predecessor, the 260, which is cast crank and pistons, 2-bolt mains.
Unless you're getting very radical, the stock cast crank and pistons are more than up to the task of performance upgrades, other than supercharging.

Thanks for the replys!

All Merc 5.7's(including the 350 Magnum) use a 2 bolt block, cast crank and cast pistons. The Vortec engines use powdered metal connecting rods, which are decent and better hypereutectic pistons.

ASK YOUR CHEVY DEALER,WITH THE ENGINE NUMBERS THE CAN TELL YOU.MERC GETS THE MOTORS FROM GM

If you want to prove to yourself what parts are different, go to mercrusierparts.com and look up the various engines and cross reference the part numbers between the 5.7L and 350 Magnum. You'll see they are all the same.