Carb, question which will work better

[weyrauch]

Hi, I have a 1984 Sunbird 20 foot fiberglass, open bow pretty deep v, I built a 400 sbc with a mild comp marine cam, open exhaust, vortec heads, right now I have the factory 5.7 260 hp quadajet carb 600, I can only get 4600 rpms at 52 mph with a alum 13.75x21 pitch prop, Do do you think a 750 holley would be a better choice, I,m thinking I could be running short on fuel, any suggestions? Would a stainless prop be better.

 

[sharkin95]

Re: Carb, question which will work better

The rochester quad can handle that engine load, if it's running good I would'nt remove it. what rpm should that engine top out at 4800-5000 rpms?

 

[weyrauch]

Re: Carb, question which will work better

The rochester quad can handle that engine load, if it's running good I would'nt remove it. what rpm should that engine top out at 4800-5000 rpms?

It could spin 5000, but 4800 is all IO want to push the drive, What would you think I could do for more speed, Or do you feel im close as I can get with the set-up, Thanks

 

[sharkin95]

Re: Carb, question which will work better

go to stainless prop 14 x 20 pitch ...hp should increase 1-2 mph rpms will go to 4800-4900. The only other thing I can think of is to install wings with a 20ft boat going 52mph..lol

 

[Bondo]

Re: Carb, question which will work better

Hi, I have a 1984 Sunbird 20 foot fiberglass, open bow pretty deep v, I built a 400 sbc with a mild comp marine cam, open exhaust, vortec heads, right now I have the factory 5.7 260 hp quadajet carb 600, I can only get 4600 rpms at 52 mph with a alum 13.75x21 pitch prop, Do do you think a 750 holley would be a better choice, I,m thinking I could be running short on fuel, any suggestions? Would a stainless prop be better.

Ayuh,.... Welcome Aboard,... The Quadra-jet will flow up to 800 cfms,... That ain't yer problem...

'course, if the carb is outa tune, 'n not set up for the motor, it's irrelevant what it flows...

What does the spark plug colors tell ya,..??

What outdrive ya got,..??