no spark at plugs

we changed out broken 305 to a 350 in an 85 gmc.after installing new cap,rotor,coil and even another distributor we still do not have any spark to plugs.i have checked all ground wires and retighten all connections. we have 12v to distributor and 9v while cranking.any ideas?

Make sure the rotor is pointed at the #1 cylinder while its at TDC, and installed correctly. #1 cylinder should be the front one on the right side as if your looking under the hood, standing in front of the car. That is if its an 80's Chevy SB 350.

Since your getting volts to the distributor that really only leaves the rotor, cap, wires, or plugs that could be wrong. Is your primary coil at 2-3 ohms resistance as well, and working? The same thing happend to my truck and it was because the coil was shot. I don't know what else to suggest other than those possible problems. It can't be much or a big problem since the distributor is getting volts. Good luck with that.

i take it you are using a good ole hei ignition system. sounds like the module inside the cap is bad. remember the coil is self contained in thi setup. try a new mod.

i was about to say the coil pack or ign system, those things have a rep for rustin up and fauling up and not send any spark

thanks for all of your help. the esc unit was bad so i wired around it and now have spark.