canuckvetter1

My 72 has a 400sbc with a Edelbrock RPM Performer intake. The carb is a holley (list 3310-2) I don't know how old. The throttle responce is hideous from 750 to 3000rpm. I have a 1" spacer under the carb so the breather will reach the cowl induction box. 3 different mechanics have tinkered with it but the lean/rich mixture doesn't seem to be right. Does anyone have any input? Do I need to up date the carb? Is the spacer the problem? At low RPM the car chuggs like it wants to get up and go but when I hit the go pedal it hesitates and sometimes stalls. I have a M21 with 3.08 gears so I know it is a little slow out of the hole. :banghead:

yellow 72

You didn't mention your cam, a long duration cam and tall 308 gears will be soggy at the bottom.
FWIW I use a four hole spacer on a RPM manifold with a 600 dp Holley and my throttle response has been compared to fuel injection :smash:

Mike :cheers:


[Modified by yellow 72, 10:12 PM 8/16/2003]

Ganey

More info. needed as Mike said.

If you have an open spacer, a 4 hole spacer could fix.

redwingvette

As Mike and Ganey said, the cam puts the power curve where it needs to be based on drive tran. The RPM intake is made to give improve power at the higher RPM range. It is good for engines that build RPM's quikly with a slight loss to low end performance. If there is a hesitaion when you first hit the pedel then you might need to adjust the accelerator pump jets/cam to make sure you are getting enough of a fuel shot to let the carb catch up to the increase in air flow.

The Money Pit

I run a 240 degree hydraulic cam in my 406 with the RPM Q-Jet manifold and no spacer. Ther's no way I could hit full throttle from the launch due to the torque breaking my P295 50's loose. I would loose the spacer,at least till you figure out what else is wrong.Could be a vacuum leak,but without knowing the cam specs and CR I'd just be guessing here.

vettfixr

I would check the ignition timing first. Read Lar's paper on ignition timing in corvettefaq and do what he says. These cars came with notoriously slow timing curves for smog and getting the curve right will feel like you added 50 horsepower. I would also lose the spacer until you get everything sorted out.