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Re: gas engine choices for a repower
Posted: July 15th, 2016, 11:01 am
by bud37
Its raining up here today.

So a little more hp....did they just create that with more cam duration ( overlap ) , or better head design??? Would all of the higher hp 7.4's be like that even from crusader etc, did they all just buy crates from GM at specified HP then add there own stuff.
Wonder if they all have the offshore cast parts as well ??
Re: gas engine choices for a repower
Posted: July 15th, 2016, 11:07 am
by bud37
Its raining up here today

How did they make the extra power ,more duration ( overlap) or better head design ??Do all of the 7.4's at the same power do it the same way, I guess what I am trying to say is do all of them Merc, Crsader etc just buy GM crates at a specified hp then add their own stuff ??
Whoops didn't see the page change

Re: gas engine choices for a repower
Posted: July 15th, 2016, 12:22 pm
by waybomb
If you change the hp/torque, then you also have to consider re-propping, maybe even heavier drives. And if you do a different hp long block, you can expect upgrading carburetor as well. And completely different manufacturer, then you have to change rigging and wiring. And if you have a closed cooling system, expect the need for more heat removal. And more hp means using more fuel.
If it were me, on a pleasure boat, I'd replace like-for-like, exactly.
I know all too well what horsepower and torque changes cost. Starting at 3 props at 3500 each. 6 carbs. and on and on.....
Re: gas engine choices for a repower
Posted: July 15th, 2016, 5:56 pm
by bud37
waybomb wrote:Qr Bbpost I know all too well what horsepower and torque changes cost. Starting at 3 props at 3500 each. 6 carbs. and on and on.....
Now that sounds like some first hand add on pain....seems like its almost as much or more to change all the peripheral stuff. Believe that we would stick with the same power/ torque range as the originals though.