This is the stock bottom end of 350 MPI after four seasons and about 350 hours running a Whipple with 4.5lbs boost with LOTS of continuos WOT and higher rpm cruising under boost. Rich enough to be safe but not so rich that it's washing the cylinders down. No signs of detonation either. Stock Hyperucrackedit's are doing fine at this power level with a safe tune from Whipple.

what kind of hp did it make and what was max rpm

What Dustin said, I had Bob @ Full Throttle Marine rework my Merc 6.2 a couple years ago
Aluminum 2.02/1.60 heads, dropped compression down with fordged dished JE pistons, a slightly larger cam/ 1.6 full roller rockers, Stainless Marine Exhaust and 6 PSI from a 2.3 liter Whipple dyno'd at 600 HP @ 6,000 rpms and 575 TQ starting at 3,000 RPM, cheap? No, but I picked up a solid 20 MPH to 90 MPH in a Donzi Classic 18 and the acceleration and looks on people's faces when we go by is priceless, I cruise at or around 3,000-3,200 RPM's and it quit efficient actually. Get with a good builder and they can hook you up on a conservative build that will make your boating experience nite and day different if you choose to go with a little boost, I'm glad I did its been a complete blast!
I believe the SB mag motors are cast pistons and cranks, the 6.2's had the forged cranks and cast hyper pistons least that's what mine had, we reused the crank, I wanted to get away from the hyper pistons and go with the forged while we where in there we went .030 over so it's a 383 now
Steve

What was your static compression and cam specs?

What size injectors did you run?

I believe the compression with the dished pistons was 8.8:1 if I recall might have been 8.6:1 think final was around 12.4:1, as far as the cam I believe it's a mid 230 duration low .500 lift don't have the card on it, injectors? It was a standard 6.2 kit with 2 additional injectors added. Give Bob a shout at Full Throttle, I've been very pleased with it. Forgot to mention the 350's and 6.2's don't come with any oil cooler and a small 4 qt pan, so we also added a 7qt pan and medium size cooler.
I've got around 130 hrs with the blower and last scan less than an hr was above 5,500 it mostly sees 3,000-4,000 when not idling in and out of no wake zones, I can tell you full boost comes in at 4,800 cuz it feels like it shifts into high gear and its off 50-85 happens in a matter of a couple seconds, literally pins you back in the seat, it's a hoot, the fit and finish of the Whipple is really a very nice piece, in my application I had to stay Smallblock and I wanted something that didn't require a scoop and there was no room for the procharger, and personally I love the polished rooter sittin on top of the engine, let alone the whine it gives off under boost. :)
Ill add this mine has the Merc ECM555 and I wanted to stay with the computer, some will say no one can tune them, that's simply not true Dustin did mine and its a special tune for what changed on my engine.

I have 6.2s and down the line I could see myself wanting to push them a bit. If you don't mind me asking, how much did that setup run you? Everyone always says BBC is cheaper but I would like to compare numbers.

Trying to keep all the upgrades mentioned straight. I have a 2010 Nordic 22' EVO that I want to keep SBC and MPI so I'm trying to search out my options.
Of course Whipple is one but they are upwards of $7000! I'd think heads, cam, exhaust and re-flash can be done for much less $$

I did the upgrades and unless you do the work yourself....Whipple is cheaper

If you want a big change go with boost. I went with bigger cam XM270HR better flowing stainless Manley race valves, Vortec head port clean up and new tune. Gained 200rpm at WOT. I had to go into one motor so modifying made sense, but don't expect big results without boost.

1999 350mag mpi looks to have forged rods, cast pistons and crank.

zoom in on crank
[ATTACH=CONFIG]526568[/ATTACH]

[ATTACH=CONFIG]526569[/ATTACH]