NickFrantz

Looking to get a little better performance out of my motor. New to gas stuff being a diesel mechanic. Looking to do an intake, replace valve springs, and possibly roller rockers. Looking for what guys have done, best springs to use and is there clearance for higher ratio rockers?

Port Monster

There are a crap load of conversations out there on how to improve performance on this motor. Do a quick search. Identify your budget to get the advice homes in a little more!

MCKILLOP

Hi Nick,

Com cams makes a nice hydraulic cam and lifter kit for around $1200. That would be a nice ugrade with a good exhaust. Is you engine an mpi or carbed? Mark Boos can at Precision Marine, Inc. can build an ECU tune for you to match the cam set up. (www.pmefi.com)
Another option would be to give Bob Madera a call at Marine Kinetics. He has some nice mild packages for these engines as well.

NickFrantz

It is a carb motor and is a mag. I have been searching but nothing answered any of my questions. The motor is in the boat so no can. I'm only doing a few little things. I wouldn't even be doing rockers but am replacing springs due to the fact I have no idea how many hours on them so since they are off why not upgrade.

MCKILLOP

I'd save the money for fuel and beer if you don't want to do the cam.. Nothing is worth doing without a cam. Believe me, I have tried.

NickFrantz

OK I did not ask about a cam. Info on my question would help.

Griff

You will gain close to nothing by switching intakes, valve springs or adding roller rockers.
The stock springs are matched to the cam and should be replaced with the same.
The stock magnum intake flows pretty well and changing it without a cam change is a waste.
Stock cam is .510/.510, 220/220 on a 115.5 lob sep. It is a GM cam.

dereknkathy

ok, you wanna change springs cuz you are worried about them. i think these guys are saying they are stock springs in a stock application and are not short-lived like the hi-lift stiff springs found in more exotic set-ups. if you just wanna do a little, do the exhausts. that is something that rots out and will kill a motor. plus, pretty aftermarket exhausts make it look like engine is done up. and as soon as you upgrade anything, you need better exhaust anyway.

NickFrantz

Yes I want to change them because I've been told over and over and read a bunch about changing after a while due to fatigue on them stock or not. Either way $100 in new ones is cheap insurance and piece of mind. All I've read is exhaust is a waste unless you do other stuff such as a cam. I don't see dropping $1500 plus on exhaust for no gain as an option. I've called and talked about exhaust and only been talked out of it. If I did what works to keep my changeable exh.

rivermonkey

On my 24 outlaw with a 385hp 454mag efi, I changed only the exhaust, stockers to Dana performance exhaust. I noticed a big difference! Got on plane faster, had more midrange pull and put me on the rev limiter so I was able to prop up one pitch, from 23 to a 25. That alone got me 2 mph on top. Most importantly, it sounded waaaaay meaner!!