bobsbillets

That 330 H.P. big block your buddy's boat has will produce alot more torque than your 300 h.p. 350 small block will. He is runnin about 10 mph faster than you. I would say that is fairly close given the differences in the engines. You may gain a couple mph by the 17P prop..

Bernarde

I guess I should have said that it is the same boat as mine. My buddy is also running a small block chevy. And that is why I am wondering where I can make up the loss, I havent had a chance to see what he is running for a prop yet though

sprink58

Yes...the stock secondary spring in the secondary diaphram is very stiff. Holley sells a spring assortment kit that lets you customize the secondary opening but I never have had any luck doing it with a marine application.

I have run 600 CFM Holley Double Pumpers on 350 Chevy's with great success. A 650 Marine is hard to find...good luck.

Before you buy another carb ($500 new ) go back to basics. Make sure you have no blockage in your fuel system...I have seen as have others a dirty fuel filter or water separator restrict fuel pressure enough to cause a problem like yours. Double check all your lines for kinks or restrictions.

onesickpantera

iTrader: (1)

I still say you are down on power and you are trimming too high trying to get rpms, making excessive slip. Borrow your friend's prop and see what happens.

Griff

Not every 3 blade prop is the same. I think youy need to test a 17 and 19 Mirage Plus to see which works better and pulls the correct rpms. 600cfm should be enough carb. A 650 might help top end a little, but start with prop testing befroe you worry about that.

Bernarde

Thanks for all the input everyone it is greatly appreciated. I am going to give everything another once over and try to do some prop testing in the next couple of weeks. I'll keep you all posted, thanks again guys.