1994 220BR, engine upgrade?

[davidmarkman]

Hey all, I'm new to the forum but a long time boater. I just bought a really nice 1994 220 bow rider. It has the 5.7 (260hp) and an Merc Alpha drive. The motor is getting a little tired and has a leak from the rear main seal, so I'm planning on pulling it this winter and at least doing the rear main seal. I have a GM 350HO crate engine sitting in my garage that I had intentions of putting in my Camaro, but the car is long gone, so I'm thinking of swapping it into the boat. I have lots of experience building the SBC in an automotive setting, but not much on the marine side, and I'm sure there are a few little things that are different. I'm sure it will bolt up, but is there anything I should change out on the motor for marine use? BTW, this rig will NEVER see salt water. Any suggestions are appreciated.

 

[BarryCF]

Brass freeze plugs, marine camshaft, head gaskets to start. The carb, alternator, starter, etc. all must be marine certified.

If that engine is FI, you have the problem of the O2 sensor and completely different fuel mapping.

 

[davidmarkman]

It's just a long block, so no worries about the fuel system, I'm sticking with a carb. I figured the head gaskets would need to be changed and the freeze plugs, I know the plugs that are in it are zinc coated so obvious problems there. The cam is similar to a ZZ4 cam, but not a roller. I know the ZZ4 cam works well in a marine applciation.

 

[ShamuToo]

Brass freeze plugs, marine camshaft, head gaskets to start. The carb, alternator, starter, etc. all must be marine certified.

If that engine is FI, you have the problem of the O2 sensor and completely different fuel mapping.

As noted above, plus marine gaskets for the intake manifold, windage tray from your marine engine swapped to the crate engine, use your merc oil pan. Fel-pro make a supreme set of marine gaskets for SBC. Also, if your crate motor is not built using the Vortec heads change them out, it will require a new intake as well. An Edelbrock performer will do fine. The carb will sit 3/4" higher, so make sure you have clearance first. It will add about 40 HP and fuel use will go down. Don't waste money on a roller cam, you'll never turn enough RPMs.

 

[davidmarkman]

Ooo, I didn't think about the windage tray and oil pan, good point. The 350HO has Vortec heads on it, and I have a Performer intake for it. I'm anxious to see the performance gains, right now it does 48 on the GPS @ WOT, and cruises nicely at 40.