Lots of questions

[38special]

I,m in the process of replacing my transome and stringers along with a bigger engine in a 78 tri hull. Are the mercruiser out drives limited to a certain RPM? Mine is an mc1. The reason i ask is because i am ready to start ordering parts for the engine, a 4.3 vortec. I need to choose a camshaft and match it to what ever the the out drive is good for.

 

[dubs283]

Re: Lots of questions

most marine sterndrive/inboard engines are designed to have a WOT somewhere around 4500 rpm depending on long block set-up, ignition components, etc...

an MC-I drive would be able to handle a 4.3 liter engine producing roughly 4500 RPM give or take - that is of course with the proper gear ratio in the drive (mercruiser never put the MC-I behind a 4.3)

 

[Bondo]

Re: Lots of questions

I need to choose a camshaft and match it to what ever the the out drive is good for.

Ayuh,... Ya want a cam that builds power from Idle, to 4800rpms....

Most of the aftermarket cam companies list what you need as RV / Marine cams...

4.3ls have weak cranks anyways, no reason to Hotrod it to have fun...

 

[38special]

Re: Lots of questions

Ayuh,... Ya want a cam that builds power from Idle, to 4800rpms....

Most of the aftermarket cam companies list what you need as RV / Marine cams...

4.3ls have weak cranks anyways, no reason to Hotrod it to have fun...

I have my eye on some je pistons and eagle rods to lighten up some of the swinging weight on the crank. 20% lighter is the claim. Are there any oiling secrets on the 4.3's?


My tri hull got up to 40 mph with a good running 3.0. Am i wishful thinking about 50 mph with a 4.3? My boat's not what i'd call a big tri hull, 17' and not as wide as most others i've seen. I plan on buying aluminum exhaust manifolds and risers to help keep it light. Can i run a distributor also?

 

[Bondo]

Re: Lots of questions

Can i run a distributor also?

Ayuh,... I think ya Gotta run a distributer, don't think it'll run without 1...

You're really Wasting abuncha money on that motor...