Hello everyone, New member here. I would first like to thank Brent Mills for the warm welcome. The problem I've run into is a stumble with the engine in my sons 71 El Camino. The engine is a 454 big block chev taken from a large 97-98 truck. Before my son got the car an Edelbrock Performer2 intake was installed along with a Holley 750cfm sqarebore Vac. secodary dualfeed carb. A GM HEI distrbutor was used and the stock GM sparkplugs and Accel 8mm copper core wires installed. Keep in mind this was a computer motor. All of that is gone and a Pete Jackson gear drive installed on the stock roller lifter cam. A set of Hooker headers were also installed and the initial timing set to 12 deg. B.T.D.C. The accelerator pump diaphram and check valve have been replaced and the sprayer head upsized. An advance kit for the weights in the distributor has also been installed to get proper advance curves. The Vac. advance also operates properly and the sparkplug gap is 60 Thousands for HEI. The stumbling only occurs at lower RPM if trying to accelerate quickly,otherwise the car will smoke the tires at just about any speed when floored. Thanks ahead of time for any suggestions,Blown Burb.