I have purchased an HEI distributor but am not sure how to hook up the wiring and vacuum. Also need to know how to wire tach with new HEI system. There are two wires comming from firewall that connect to the same terminal on existing coil, new distributor has two prongs for a pig-tail, not sure if I use the same wires, and if I do which one goes where. Thanks for all your help guys.

Thanks AGAIN,

Brian

Of your two wires coming from the firewall one of these is a resistance wire coming from the ignition switch, the other is from the starter solenoid which delivers a full 12 V to the coil when your cranking the engine. You need to deliver a full 12 V source from the ignition switch to the HEI. You cannot use the factory resistance wire, you'll need to run a new wire.

The connection to the HEI is to the terminal labeled BAT. Your existing wiring from the starter and your new 12 V wire both go to this terminal. The other terminal is labeled TACH, this is the connection to your tachometer.

Connect your vacuum advance the same way as your points distributor.

You need to deliver a full 12 V source from the ignition switch to the HEI. You cannot use the factory resistance wire, you'll need to run a new wire.
Correct, you need to replace that wire ( the one from the firewall bulkhead to the coil +) with a new wire. Use 12g wire. Also be sure that wire has voltage in the cranking position. If not, also wire the the one that comes from the Starter "R" terminal to the HEI, BAT terminal to give it power when cranking.

You won't really need the yellow bypass wire from the starter solenoid with an HEI but it won't hurt anything to go ahead connect it either.

thanks guys, as always you have been a HUGE help!!!