Logo
FULL SITE MENU

Change over to 4 barrel carb

D

dsaville

New member
"I have a Volvo Penta 500A ass

"I have a Volvo Penta 500A assembly, basically a Chevy 305 with a two barrel carb. I want to change the carb and intake manifold to a 4 barrel setup to increase the horsepower.

Questions: Does it make any difference what brand of manifold I use? Anything special about the Volvo Penta manifold? Any recommendation for a certain brand of 4 barrel marine carb? Know of any issues with the linkage? Anyone have a recommended source of supply?"
 
"Dave
I would not switch to a

"Dave
I would not switch to a four barrel carb. I hate to say this but the 305 in most boats was a under powered dog. It didn't get any better milage then the 350, and was way down on power. The old rules about horsepower from 4 cycle engines apply. To get more power you need more fuel, more cam( most inportant) and where you can more displacment. Ok 4 barrel might help some, but could be a problem setting up, runablity, reliablity. Also more fuel to use it properly you need the valves open longer to intake more charge, you need higher compression, ie. different pistons, different cam. The more you try to hot up the 305, the more money you dump in, small gains, big running problems.
Number one rule for 4 cycle gas powere, no replacement for displacement.

So what I'm saying is if it was me I wouldn't put money into changing the carb, small gain, big price. I have built up, repaired and replaced engines for 40 yrs. Have had customers and friends outfit boats with 305 skipping the 350 thinking they where getting power and gas savings, didn't work that way. Enjoy this boat learn something, get engines you want,in next boat with money you saved from not doing this.

Sorry if this was not what you wanted to hear.
If you go ahead, use marine carb not street carb, don't get to wild on cfm (cubic feet per minute)as the cam only holds the door open so long and all the gas in the world can't over come that, to much flow is dangerous. ALso I expect the carb to cost up to $500.00 dollars, in take manifold to match not sure, gasket kit etc, your looking at maybe $1000.00 dollars for may be 2-3 mph if lees great worth it only you can say Good Luck Sir,"
 
Thanks for the information. I

Thanks for the information. I think I'll save my money and forget this idea. You have been most helpful.
 
Back
Top