I have a 66 chevelle with a 283 bored .030 over with a cam a step up from stock. performer intake 650 holley carb I changed over to a hei distrubutor. My problem is when i get it up between 4,000 to 5,000 rpms in any gear it starts to miss and lose power. I checked timing, and done a rewiring job using a kit from mad electric and i put in all new wires and plugs and still misses. before i start dumping money into a better ingition setup i what to make sure i am heading in the right direction any help is appreciated

Hi, try a new cap and rotor ,check plug wires see if you have one breaking down and loseing fire, New doesn't always mean good, Slim

Check the distributor too...

Ricardo

i have put in new hei distributor, new fuel pump still misses under load
Bill

Did you make certain that you are not still using the resistor wire that would have fed the old coil? If you are using that, you are not giving full voltage to the HEI. HEI needs the full voltage, points didn't.

How old is the distributor? If it's an older GM unit, try a new coil and module. The early GM HEI distributers used an inferior coil compared to the later models. Even a newer coil can break down over time. Also, check for play in the shaft, both laterally and longitudinally(sidewards and up and down). Shouldn't have more than a couple thousandths side to side, and 15 to 20 thousandths up and down. Steve