How can i boost my old 350 260hp

[Stephane]

My engine is a OMG 350 260hp.

I want to boost my engine by 40hp. I am looking for the cheapest way to do that !

Actually i do not want to open the bottum of the engine. I have no problem to change cam, carburator, ignition point for electronic ...

somebody have a suggestion ?

[mikev]

I would port and polish the heads or swap them out for newer vortech heads then crane marine cam and a hi proformance intake and carb. get dennis moores book Small-Block Chevy Marine Performance for cam selection. I would do a compression check and make sure it is good before spending alot of money on the top end if the lower end is worn out.

[Stephane]

Seven of my cylinder was at 155psi and one at 40psi. I changed the defect exhaust valve and remake the seat and now all of the cylinder have a compression of 155 psi.

[Rootsy]

for the price of cylinder heads these days i wouldn't waste my time on reworking stock heads...

what year is your motor?

a pair of vortecs, performer and a quadrajet and the right camshaft should put you in the 330 crank hp range pretty easily and allow use of all of your existing accessories and such... reuse your old carb... you might have to do a bit of jet, needle and hanger tweaking though...

[tmdog]

MIKEV gave a good answer and I would go that route. Horsepower = Money- There is no cheap way to make hp. I can attest to that. In the past 4 yrs three tear downs of engine. From cams,lifters, roller rockers new heads ,intake and tricked out carb not to mention fresh water cooling. My son and I did all the labor. Cost for all these mods, I rather not say. Thousands is the best I can mention. When somebody asks me what I am running in the Donzi I say ten thousand, :eek!: not 350 sbc. :lightning :lightning

[tmdog]

Rootsy - - good advice

[Sierra]

The bottle will do the trick, with little $$$$$

[mikev]

hey stephane did you ever figure out if the other issue you were having was your carb?

[Stephane]

First of all il will remove my carb for reman !

After that i will test the boat again to see if the clean up and adjustment will do something good. Hi hope that will do a difference. If not i will work on the engine next winter.

Many thanks for help and comments

[Sierra]

Stephane its hard to get 40HPs from a carb. If you want a quick 125HPs at a touch of a botton get an NOS system for about $400.00 US and maybe two hours of work with two beers. Check JEG'S #741-05001

[Walt. H.]

That NOS bottle will empty real fast on a boat, unlike a car that has much less resistance to over come. Unless your not looking for that 3 to 5 minute blast across the bay etc.

Plus NOS put a tremendous load on the engine's bottom end. :smash:
I would you go the way Rootsy suggested, in the long run it will be cheaper and you'll be happier with the performance results. :yes:

Just my 0.02 worth of advice with close to hundred thou lost do to experience. :wrench: not bad for a 52 yr old. :tongue:

Walt :checkered

[MOP]

When looking for more power a big consideration is the condition and hours on the engine, to get any appreciable HP you need to get inside the motor. Then it becomes a matter of $$$, to get to 300 I think that would be achievable with a good cam, heads, decent exhaust and a good carb to feed it. A good winter project, do some parts shopping you can save quite a bit with good condition used stuff that turns up both here on this site and on Ebay.

Phil

[marcdups]

If I win the power ball tonight I am gonna call GEOO :cistineb: :cistineb: :cistineb:

[marcdups]

And go do some helping in Florida while he fixes all that needs to be addressed, dunno bout a f :idea: rd though !!!!