i gor an 86 cutlass with 307 all the emissions cats y pipe and egr valves were taken off and true duels with glass pack in its place the stock qjet was replaced with a 1850 holly 600cfm. oh heres my prob when i got it it would idle ok but hesitate when u would exselorate then it started flooding real bad so i rebuilt the carb and it runs good but when u initialy take off it hesitates a little but not as bad ive tryed adjesting it but im thinkin the 600 is a little big for the 307

 

Your accelerator pump is not adjusted right, you have the wrong cam on the pump arm or your squirters are the incorrect size or a combination of all three. You should have stuck with the Qjet and rebuilt it.

 

X2 - could've used a non-pollution Q-Jet - better mileage, too.

 

it was already on the car when i got it and he didnt have the qjet

 

I know the problem.

You're tring to put a higher performance carb on a 307

Nobody asked which disturbor is on it? If the Q-jet is gone, along with all the emissions, you need a vacuum advance distro, not the 7 wire computer controled one

 

x2 on checking distributor and timing.

Then look at your secondary spring on the carb and the accelerator pump.

sb

 

If the stumble is off-idle, I agree on the accelerator pump adjustment to linkage, which should be .050.
If that original distributor is still there, without vacuum or centrifiugal advance and low compression, try setting the timing about 10 degrees advanced - should help the stumble.
Also set the mixture screws with a vacuum guage - more help!

 

thanks for the help. with the distributer can i go with a sbc or does it have to be an olds

 

Chevy WON'T interchange with Olds!! They even go different ways! CW vs. CCW
Thermostat, distributor cap, and some spark plugs are about the only things that will!

 

X2 on the dist. And I'll add that some of the vacuum lines may be an issue also. There was alot of smog items on that engine, and the normal more air and fuel routine was ineffective. I remember trying to run an open air filter element on those engines and the system actually under performed.

 

I have seen people take the secondary spring out of a holley carb to make the secondaries open faster and cause this sort of stumble. (Bog) Chased my tail for days trying to figure out the problem.

But you have to have the ignition sorted first as well as any vacuum leaks as noted above.

sb

 

yea i re did all my vacuum so thats set i just need to change my distributer. this secondary spring is that the double spring on the throttle inkage