bitsamonkey

Hello everyone, first post on this forum...
I've got a 1999 Crusader 454 carbed 350hp engine in a straight inboard 25' CC. I'm going to pull the motor soon to address an oil leak and was contemplating some upgrades to shed unnecessary weight and maybe add a little efficiency in the process. My thinking was aluminum/stainless manifolds and risers and an aluminum intake would be a good start. Probably save over a hundred pounds. My parameters are good torque, smooth idle, no reversion and highest MPGs at 2800 - 3200 Rpm. I'm running a 16" x 18" 4 blade prop with a med cup, 1.52-1 Velvet Drive and get about 28 mph at 3000 and 14 gph.
Is it worth it?
What model intake for a Quadrajet?
I want to keep the manifolds freshwater cooled.

PS: I know this isn't the most exciting stuff for you guys, but there is a serious lack of gas inboard know how on regular boating forums. Just a bunch of 4 stroke vs. 2 stroke and Regulator vs. Contender. I like to do my own wrenching and enjoy a good running/optimized setup.

jeffswav

Welcome to the site!!! What kind of boat is this?

Andy

Can you do a compression or leakdown test? How many hrs.

bitsamonkey

Thanks, it's a 25' Whitewater center console, 24* deep vee, 8ft beam ~6000 lbs. Engine has about 900 hrs and runs great. I have not done a leakdown or compression test as it really does run smooth with plenty of power.

getrdunn

iTrader: (7)

At 900 hours I would really consider doing a rebuild. Assuming all is good it would be very inexpensive to at the very least new bearings and have your heads gone through. I would mic all parts or have a machine shop check them for you. I know that's not what your asking about however thought I would throw it in there anyway. The performer rpm intakes have a Qj flange on them otherwise adapters are readily available. A 383 would be ideal in that boat however I realize your not looking for any real gains. Go to the advertisers section here on the forum and check out Cp and the others for exhaust. Emi's might be a good way to go also. With that heavy of a boat I wouldn't really expect much with out other mods other than knowing you lost some weight. I just can't see any real benefit. When I need to lose 100 pds I just throw one of my redneck buddies over board. LOL... The 200 pds of beer always stays though.

bitsamonkey

Yeah, it's my 200lb buddies being so tight with kicking in some gas money that's got me thinking all of this through in the first place. What do you guys think of the 6.0 MPI? There's a hell of a deal on one near me, I just don't know if it'll produce the kind of torque that's needed for this boat.
What about an MPI conversion on my existing motor?

getrdunn

iTrader: (7)

I am sorry regarding the earlier post. For some reason I was thinking you had a 350 CI engine.

I gave up on having the buddies chip in for fuel many years ago. If I get them to buy the beer I am doing good. Never forget one day when a so called friend flipped me a 20 at the gas dock. What the??? LOL...

fireboatpilot

With 900 hours on it I wouldn't consider pulling it and not rebuilding it before putting it back in. If everythings OK inside it should be a fairly inexpensive rebuild. Change the exhaust to some EMI's, Powerflows, or GILS which can be had for cheap. An aluminum intake, change out the Rod for an Edelbrock 750, also cheap and reliable. Bump up the cam kit a little and there are some cheapy aluminum heads around complete for a grand a pair. They'll do just fine for the power range you'll be in and save you another 100 pounds or so.

Hey John, did you take his $20? LOL

getrdunn

iTrader: (7)

No, didn't take the twenty. I tossed it in the water.

Griff

I dooubt you will ever recover the costs in fuel savings that an exhaust system will cost along with an intake manifold. You are looking at $2000-3000 in improvements. It will take forever to recover the cost even if you could gain 5-10% more efficiency at those rpms. You would recoup the $$$ in about 10 years and then you would need new exhaust again anyway.