I am trying to decide should i run a 30cc or 50cc accelerator pump on my holley ?

See what I have is a 1972 ford 429 8:5:1 cr mild motor, no smog/no egr, and no a/c, a 160 thermostat,dual 2.5 exhaust, timing tweeced,1 inch 4 hole carb spacer and a holley 3310-750 cfm single pumper carb would I be better to run the 30cc or 50cc pump, the 30cc is relatively small and usually on like smaller carbs 600cfm I belive and smaller and what kinda power do you think my motor will spit out?

 

Unless you are running a true Hi-preformance engine (you are not) the 30cc pump should be more than adequate. The 50 cc pumps are for racing mainly and 99% of the street motors that have then don't really need them. BTW, the 30cc is the standard pump and isn't small. Both my 428CJ's ran the 30cc pump on the 735CFM carb and it was a true factory HP motor. All the street 3310's come with a 30cc pump for a reason, they don't need more.

 

thanks it has a 30cc on it right now just I also had a 650 double pumper that had the 50cc so just wondered ,about how much power do you think my motor will make? i would like to have enough to get my f-250 haulin

 

Double pumpers were designed for real race cars. Very few street cars need one or can really use one and even less street trucks. I used to street race for money and even titles and I never ran other than a 30cc pump or a vacuum secondary carb. Never lost a title race and lost very few money races. The street is a whole different set up than a race track. To many people are always thinking bigger is better and if it works on that guy's race car it will work on my street machine. In all but a very few cases that thinking is false.

 

Thanks, you seem good with carbs maybe you can help me. Alright I have well the holley 3310-750 cfm on my truck now when I first put it on which wasnt but a few months ago it idled like a dream and would rev easily no problems, or hesitation it has the stock 72 jets are those about right or they to bog or to small? Anyways the truck sit maybe 2 months but It was taken care of and all ,now when i try to start it it dont want to stay running or anything, not even idle and im puzzled, nothing has been changed ,so you think maybe needle valve sticking? This carb was all rebuilt and ran perfect before on the truck.Im puzzled.

 

I can try to help, but if I was all knowing I wouldn't be on here. Has the engine back fired recently, like on start up after storage? All it takes is one little hiccup and the power valve will be blown and you will have the symptoms you have. Usually a stuck float on a Holley will dump enough fuel to over flow the vent on top of the carb. You can check easy enough. There is a brass screw in the side of the float bowl. Start the engine and remove the screw. Fuel should just barely dribble over the lower edge of the hole. If it does you have a good needle valve and float level. Check both front and rear float bowls, they each have there own valve and float and are adjusted independently.

 

thanks, yea it has backfired since i tried restarting it after it sit, but before jsut walk out crank not even touch the gas started right up,now I crank and crank it will hit and run then stop,i guess ill have to check my powervalve it was new and the needlevlaves and gaskets seals were all new to but ill double check everything just to be safe.

 

your over carbed as well, 600 or 650 is plenty for a stock 460

 

KubotsOrange76, I agree that it is a bit much for carburation. My 428CJ which turned 6000 RPM only had a 735 CFM carb. But the vacuum secondaries will cover up the large CFM a bit and the 3310 should be ok. I would say that just1me have a blown power valve, which leaks fuel from the float bowl straight into the intake manifold. You have to remove the front float bowl and metering block to change the power valve. I would however recommend that you pull the whole carb and install a power valve protection device in the base plate and prevent further blown valves. My old 1968 F250 with a 390 with a 600 CFM holley had 3 gas tanks, a main tank and dual saddle tanks. No fuel gauges on the saddle tanks and when they ran dry and you switched to a full tank, the engine seemed to always back fire when it came back on line. Installed a power valve protector and never lost another one. Good thing to, because I went to the dual stage power valves and at $25 apiece (then, now more like $35) I couldn't afford that.

 

yea i have thought about going down to a 600cfm but my 750 cost me, and i got a new chrome dual feed line, and all but if i can find a holley 600 i might give it a try.

 

There are an awlful lot of them out there. Just keep looking. I found 4 of the old 1850 600 CFM Holleys in a guys garage last this last spring. Really restocked my Holley spare parts supply. Free for the asking. He also gave my an Edelbrock chromed up to look pretty carb, but i will probably just use it for trading fodder. I quit using that style of carb in the about 1966.

 

yea i think im gonan try a 600cfm thats what it had before on it but i gave it away whe i got the 750 its nice to.

 

The 750 CFM (why the change from 780 which the original 3310's were rated at?) will run a 390 to 6650 RPM. And a 600 CFM is go take it to 5325 RPM. Most stock truck motors are done by 5000 if you are real lucky, usually closer to 4500 RPM. They will rev higher, but the horsepower is dropping off fast and you are just abusing the motor for ego and not any preformance gain.

 

yea ill probably drop down to a 600cfm my uncle though has a 1969 429 with longtubes and a offenhauser intake so a 750 might benefit him.

 

I have a 1984 Ford F250 with a 460 with a Carburetor that says something like made for MotoCraft by Holley, double pumper. I think it was the stock carb. Maybe a 4160 or 4180. I have replaced he accelerator pump diaphragm several times and tried to sand down the housing on a flat surface a few times but... It keeps leaking. It leaks when it is first started and stops when he engine warms up. Also it seems like the float bowl empties and it's hard to start after about 3 days of sitting, sometimes it's just easier to add gas in the throat of the carb to get it started instead of cranking and cranking. It runs good once the truck is started. Anyone had a similar experience? How to fix?