69 LWB Electrical Malfunction

[shootfirst]

I just got my truck going after new engine swap, I have replaced the starter,alternator,voltage regulator,distributor,wires plugs,battery, all parts are new I can start the motor and it seems to run fine set the timing and all that , As soon as I take it for a ride it starts running like crap and will stall within a 1/4mile and when I try to restart it it seems like the battery is junk and I have no spark at the plugs but if I jump it it will start right up and run until I start to drive it again and it does the same thing. Anyone have any suggestions as to what might be happening? I am running a MSD streetfire distributor(new) before this I had a Mallory but had the same problem and the coil was getting hot, thinking this was the problem I changed to the MSD. Any help would be appreciated.

[71tahoe]

Where are you getting power for the coil?

[Overkill67]

Make sure you have a good ground to the coil and block. When the oil in the coil heats up it will loose some of the continuity (spelling?) and start dropping power to the dizzy. If the ground is bupkis it will heat up fast and much more than normal an the end result is what you have as far as running lie crud and then dieing.

The starter may be getting heat soaked. Also check the alt. make sure she is putting out the proper voltage, if it isnt that will be why your loosing spark as well.

[cdowns]

is this an electronic or the old style points ignition?? does the manufacturer call for 12v at the coil or 8-9volts at the coil?? original resistor wiring on these trucks provide 8-9volt at the coil in the run position.// is the coil the proper one for the type distributor you're using

[shootfirst]

Originally Posted by 71tahoe

Where are you getting power for the coil?

I get the 12v from a switched terminal on the fuse block

[shootfirst]

Originally Posted by cdowns

is this an electronic or the old style points ignition?? does the manufacturer call for 12v at the coil or 8-9volts at the coil?? original resistor wiring on these trucks provide 8-9volt at the coil in the run position.// is the coil the proper one for the type distributor you're using

Its a MSD streetfire/HEI ignition and am using the external voltage regulator with no mods, I have been contemplating changing alternator to a internal regulator and eliminating the one on the firewall. It does seem like not getting enough voltage at the distributor. Thanks

[shootfirst]

Originally Posted by Overkill67

Make sure you have a good ground to the coil and block. When the oil in the coil heats up it will loose some of the continuity (spelling?) and start dropping power to the dizzy. If the ground is bupkis it will heat up fast and much more than normal an the end result is what you have as far as running lie crud and then dieing.

The starter may be getting heat soaked. Also check the alt. make sure she is putting out the proper voltage, if it isnt that will be why your loosing spark as well.

As far as i can tell my ground to the motor is tight, starter is one of those small bodied gear reduction ones Its new and I have it shielded from the headers I aim to have my alt checked tomorrow but will probably change it over to one with a internal regulator and bypass the one on the wall, Hopefully can remedy this. Thanks

[71tahoe]

Checking the alternator is a good idea.

Did you get a new coil with the new MSD?

For the electrical gurus out there, if the coil wire comes from switched fuse, and the starter solenoid goes through the same switch, could it be the ignition switch?