Hello everyone,

Your expertise is much needed. I have been trying to tackle a puzzling problem within my '73 Vette. Strong 350 attached to a freshly built TH400. I don't drive it much because I am gone for school, so summers and breaks are the only time I am able to drive it.

My problem is whenever I try to get up and go, the car doesn't want to. When I depress the gas pedal the acceleration is sluggish and the engine bogs down. Never has it died or stalled on me on the road. I changed a few parts thinking that they would be the source of my problem. I changed all of my spark plugs, new mechanical fuel pump (edelbrock), steel modulator vacuum line, electric kickdown switch functions properly, gear shift detente is spot on, new modulator, new fuel filter, new 600 cfm edelbrock carburetor with a heat insulator gasket to prevent fuel boiling, checked my mallory hyfire ignition system. Alternator has been changed a couple of years back.

- Fuel lines are clean, proper fluid levels in all components. I have tweaked with the governor governor calibration as well. The only things I haven't replaced is the battery or the ignition coil. Took the car back to the transmission shop and the guy said that the tranny is functioning as it should.

 

You mention nothing about the distributor. Do you still have the stock distributor with points? If so have you checked the dwell and the timing and the mechanical advance weights for sticking? Is the Hy-Fire just the box or you also have a Mallory distributor? Have you looked down the primary side of the carburetor with the engine off to make sure you are getting a good stream of gas from the accelerator pump?

 

My apologies, I forgot to include that I checked the distributor as well. It is not the original, it is a MSD Pro-Billet Tach Drive distributor (part no. 8572) vacuum and mechanical advance. Engine is getting plenty of gas and I just adjusted the accelerator pump to the furthest out from the carb to shoot less fuel. A little improvement on off idle acceleration, but problem still exists. Maybe I have a vacuum leak still from the modulator as the 90 degree bend from the modulator is still rubber vacuum line.

 

Could be something simple like plug wires misplaced or maybe a bad accelerator pump in the carb. You should see a squirt of fuel into the carb when you blip the throttle if the pump is working correctly. Even if the carb is new it could have a tear in the pump diaphragm if it has been sitting around for a while.

Really hard to diagnose problems like this over the internet. Hopefully someone will guess the right answer.



Rick B.

 

You didn't mention ignition timing. It is critical. You should have a recurve kit installed in the distributor, weights and springs, and set your total timing at 36 deg at 3000 rpm. This is with vac advance disconnected.