Originally Posted by P.H. 88
i have a 81 c-10 with a non stock 350 small it had points i converted it 2 H.E.I in hopes of getting rid of the back fire . i put the balancer at 0 did the finger blow out on #1 cyl with the dis cap off rotter pointing at number one firing order checked and er checked. in the begging it back fired only with a load on now starts up and back fires. help http://www.hotrodders.com/forum/newt...ewthread&f=21#
What is the timing set at. Usually a backfire through the carb is either timing, lean mixture or valves that are to tight. You may also want to be sure the HEI is being fed at least 12 volts. Shoud be the same as battery voltage. Point system often has a resistor to cut the voltage down.
Also check the firing order, pay close attention to 5 and 7 as they are next to each other on both ends and are easy to mix up