What's the difference?

[CHEETER-JOE]

between a marine motor and a street motor? I am wanting to build a sbc to replace my 6.2, what do I need to know?

[Moneypitt]

Your bank account balance is important...Other than that just build the hoursepower you want using a camshaft that will work in the desired RPM range. This means the bottom/midrange and the top end. A boat is fairly forgiving when it come to getting into the midrange. You're not trying to move a heavy vehicle on the pavement so the motor can get happy pretty quickly. As with any hipo project the bottom end needs to be bullet proof, don't spare the $ money down there. Once the comp ratio is established,(do you plan on running "funny gas") then you can cam it and work your way in and out from there..........boat weight, gearing, and how wet the boat remains at speed all have a bearing on your HP requirements. Do a little research, look at boats simular to yours and see what they have done, what worked and what didn't.......get the picture? .........Moneypitt

[CHEETER-JOE]

I am looking to build a basic 350 or 400 block with alum heads fully roller nice cam and maybe some sort of fuel injection on pump gas. Maybe around the 400hp or so range. As far as the heads, they are the same for street or marine?

[Moneypitt]

I would say yes, they are the same. However, boats are harder on valve train parts because they don't coast like a street car. If you accelerate up to speed in a car, you can feather the throttle back and cruise. In a boat, you must maintain the rpm s to maintain the speed. I other words you're gonna be reving it pretty hard all day. I strongly suggest the springs used be part of the camshaft kit, and a stud girdle is a necessity...........MP

[CHEETER-JOE]

Thanks for the info MP.

[twistedpair]

This guy used to post here a lot. You might say he wrote The Book (http://www.glen-l.com/books/smallblock.html) on marine performance motors.

[powerplay230]

CHEETER-JOE,
Not sure what they deal is on your 6.2 but if it's in one piece can you build up it. Saves you the cost of the basic longblock or is that motor even worth building up. Not sure what parts are used in them or what is available? Guys??
Rick

[CHEETER-JOE]

There is nothing wrong with the 6.2 besides lack of power, it has only 46 hours on it. I know I can just add a whipple or procharger, but I dont know what is internal in this motor. If I build another motor, I can still have this in the meantime. And it is always fun just to build a motor anyway!!

[Bondo]

Your 6.2l IS a 383..............
350 Block,+ a 3.75"(400cid) Crank............
You've got Problems in Tuning......
You Should have all the HorsePower you Need........

[CHEETER-JOE]

Originally posted by Bondo
Your 6.2l IS a 383..............
350 Block,+ a 3.75"(400cid) Crank............
You've got Problems in Tuning......
You Should have all the HorsePower you Need........
It is a 377 6.2 MPI with 320hp. In a 24' boat. I get about 55-58 mph out of it, but always want more. I would like to get between 65-70 mph out of it.