This all started after I got my 454 rebuilt and broke in. I went to set the timing and every time I put the car in gear (automatic th400) it would stall. I kept advancing the timing until it would stay running in gear and ended up at 35* of initial timing! Okay we have a problem...so I decided to check the battery and coil voltage and here's what I found, when the engine is NOT running I have 12.2v at the battery and 11.68v at the coil. When the engine IS running I have 14.1v at the battery and 7.3v at the coil. I have an MSD distributor and a MSD Blaster 2 coil, the car still has the external voltage regulator and 3 wire alternator. Would a weak spark cause the need for so much initial timing?

Many years ago someone converted the car to HEI and he also put in a starter relay, the relay was giving me problems so I did away with it. I know I need to look for that resistance wire but any other info would be greatly appreciated. Also, where can I get a wiring diagram for my car?

Looks like someone has wired the MSD to the resistor wire.
Usually can identify the resistor wire by it's insulation which looks like woven cloth...not plastic like the other wiring. And the wire itself is silver color.
Just trace it back to the firewall and replace with copper wire.

Looks like someone has wired the MSD to the resistor wire.
Usually can identify the resistor wire by it's insulation which looks like woven cloth...not plastic like the other wiring. And the wire itself is silver color.
Just trace it back to the firewall and replace with copper wire.

Okay, that was my first thought too. But it's odd that I get a good reading when the engine is not running, don't you think?

How and where are you measuring voltage?

When the engine is not running you have a constant DC voltage but with the engine running the coil will be fed a pulsating DC voltage. Most voltmeters will average the lows and the highs, especially if the changes are fast enough, and show something in between.

You might get a more interesting number using the AC scale on the voltmeter.

How and where are you measuring voltage?

When the engine is not running you have a constant DC voltage but with the engine running the coil will be fed a pulsating DC voltage. Most voltmeters will average the lows and the highs, especially if the changes are fast enough, and show something in between.

You might get a more interesting number using the AC scale on the voltmeter.

Aha! I was using the DC scale so maybe your right. I'll try the AC scale and see what happens. Thanks.

so I decided to check the battery and coil voltage and here's what I found, when the engine is NOT running I have 12.2v at the battery and 11.68v at the coil. When the engine IS running I have 14.1v at the battery and 7.3v at the coil.
Its either wired on the resistance wire, very poor connection, or severely underwired. In the case of the resistance wire, when the engine is not running, there is no current flow (only your meter which draws next to nothing) When the engine is running, current is flowing to the ignition and through a resistance wire, voltage drops. Those would be normal readings if you had a original points ignition. Since you don't, you need to replace the resistance wire.

It is only a resistance wire from the firewall bulkhead foward. Yearone has a kit to replace the resistance wire, see my post here http://www.chevelles.com/forums/showthread.php?t=129060
or you can run a new wire from the IGN switch

It is only a resistance wire from the firewall bulkhead foward. Yearone has a kit to replace the resistance wire, see my post here http://www.chevelles.com/forums/showthread.php?t=129060
or you can run a new wire from the IGN switch

If I replace the resistance wire from the bulkhead forward what gauge wire should I use? Also, I'm assuming I don't need to replace the wire form the ignition switch, correct?

If I replace the resistance wire from the bulkhead forward what gauge wire should I use?
12 gauge. You need packard 56 series terminals at the firewall bulkhead. you can get the terminals and use your own wire or buy the kit from Yearone.

Also, I'm assuming I don't need to replace the wire form the ignition switch, correct?
No, it doesn't need to be replaced, its just regular wire from the IGN switch to the firewall bulkhead. If you don't want to pull the firewall bulkhead (they can be diffcult to get apart and it is sealed to prevent mostiure from getting in) you can just bypass it. Look for a 12g pink. This wire goes from IGN switch to firewall bulkhead.

Actually the reason you get a full 12v with the car not on (does this cranking too) is that the coil is fed from 2 wires, one comes off the starter and feeds it 12v when cranking, the other is a resister wire that comes off the bulkhead feeding it roughly 8-9v when in the run position.

Actually the reason you get a full 12v with the car not on (does this cranking too) is that the coil is fed from 2 wires, one comes off the starter and feeds it 12v when cranking, the other is a resister wire that comes off the bulkhead feeding it roughly 8-9v when in the run position.
This can be sorta true on some but not all years. On some years there was a compensation for the system voltage drop with the starter engaged. The form of this compensation was to bypass the normal "ballast" resistor. This bypass was only enabled with the ignition in the start position.

It would not apply to a non-running car in the on position.