footbrake

fisherman is right, 42's are way too big. They are doing nothing. Try 35's front and back

JEFF69Z28

HAD 31 IN FRONT AMD 35 IN BACK,WHEN I MASH THE GAS IT WOULD SHUT OFF, KEPT GOING UP IN REAR UNTIL HESITATION STOPPED WHICH WAS A 41 IN THE REAR,35 IN FRONT.LAST SUNDAY IT WENT 11.64 FROM A PREVIOUS BEST OF 11.90.ALSO FOUND THE VAC.LINE TO PCV VALVE HAD A NICE CRACK IN IT SO I REPLACED IT TODAY AND WILL RUN IT FOR THE LAST TIME WITH THIS MOTOR ON SUNDAY.ALSO TOOK ABOUT 120-130 POUNDS OFF THE CAR LAST NIGHT.THIS CARB I THINK NEEDS REBUILT BUT IT WILL PROBALY BE TO SMALL FOR MY NEW SET OF HEADS AND CAM SO IM NOT GOING TO WORRY ABOUT IT ANY MORE.
THANKS FOR ALL THE INPUT....
JEFF

mopar1968

I still say you are sucking air in from somewhere, all you are doing is adding fuel to compensate for the air..

JEFF69Z28

I SAY THE SAMETING BUT CANT FIND A LEAK.

fla1976

I agree with mopar1968. Sounds like a leak. Have you checked the linkage at the butterflys. Sometimes they get worn and start leaking thru the pivot. One way to check is to spray a little WD40 on the pivot while it's running. You can spray around the base also. If it changes the idle it's being drawn thru the pivotor a leak. Or try choking it partially off with your hand, if it picks up rpm , it's getting air from somewhere.

camarotale

a 750 holley is not a favorite of mine I changed squitters, cams, jets, you name it. the only thing you can do is send it to a pro, it will work ok if you just drive it but if you want preformance when you floor it , it will hesitate,just to show I know what im talking about, turn your idle screws open to a point where it is gasing big time , like 3 to 4 rounds out and your hesitation will be gone, but you will stink up the garage and polute your oil, but it will show where the problem is and it cant be fixed without a pro getting into that carb, stop killing yourself , I have been there, I bought holley books and talked to every motor head i know and my problem was gone when i sold it and went to a 950. I suggest selling it and buying one from pro systems

dparker

:?

mopar1968

When i bought my engine from sonny's engines it came with two intakes, mopar m-1 and a indy, i tried both intakes, tuning the engine, the m-1 did not run very well idle was erratic up and down, so i went to the indy, run's perfect, come to find out the m-1 was warped 0.02 at the intake to head runners, no coolant leak but did leak air, sonny's said this was probably caused when they ported and polished runners, could have gotten too hot. just a example of what happened to me hope it help's you out.

jmlebel

You want to tune your shooters to do more than just cover the hesitation, your shooters will make all the differance in throttle reponse, your motor can make good power in conjunction with throttle responce if the AFR is kept at the right ratio as you open your throttle plates. If the motor goes to 14:1 or 15:1 AFR as you open the throttle you lkely won't notice a hesitation, as you would when real lean around 17:1 or a back fire around 19:1, but if you keep the AFR in the 12.5:1 ratio as you open the throttle blades the motor will make optimum power that you will feel in instant throttle response and torque. The point is keep tuning for optimum throttle response rather than just covering the hole. you will be very happy you did. Also don't forget the other aspects of the acceleator pump circuit, the cam, pu :cry: mp size, shooter nozzle style.

cepx111

Just curious, have you tried a 50cc pump?
On them troublesome 750 dp's I always swap out the smaller 35cc pumps and go with the bigger 50cc pumps - usually 9 times out of 10 them hair pulling WOT hesitations will go away instantly.
You need super crisp off idle throttle response for them killer lights and quick short times, especially if your foot braking.
I'd start with the primary first then go to the back if it stills needs more.
Always worked for me, goodluck Cp