Ballast Resistor

[1FATGMC]

Would a '72 Ford pickup have a ballast resistor??

I don't see one and when I check the voltage to the coil wire in the "on" position and in the "start" position the voltage stays the same.

Thanks,

Sum

[enjenjo]

No, but it does have a resistance wire from the ignition switch, to the firewall connector. If you are using an HEI, you have to bypass or remove the resistance wire. It has a braided fiberglass insulation.

[1FATGMC]

No, but it does have a resistance wire from the ignition switch, to the firewall connector. If you are using an HEI, you have to bypass or remove the resistance wire. It has a braided fiberglass insulation.

Thanks Frank, the HEI is my concern.  Are you talking about the fusible link or the wire going to the coil on the passenger compartment side of the firewall??

I seem to have the same voltage at the wire that was hooked to the old coil that I have everywhere else.

Tomorrow morning I finally get to try driving this thing maybe.  Your 2 day job took me over a month :cry: .  The other thing that is strange is that the motor seems to be about 2 inches further to the right and about 2 inches higher in the front vs. the 390.  That is where the fan is located in relation to the radiator.  I had to move the shroud over and up and make fill plates.  From the front of the crank to the output of the front driveshaft is a straight line that is parallel with the output of the rearend.  I have about 1 1/4 degrees difference in the crank to transmission output vs. the angle of the first driveshaft that is parallel to the output of the rearend.  The 1 1/4 degree is what one of the driveline companies recommended.  I guess to rotate the bearings in the u-joint cups.

Seems like I have had to modify everything to make this work.  I spent 2 hours yesterday looking a radiator hoses trying to hook the bottom of the ford rad. to the sbc.  It took two hoses with a coupling between them.  I almost called you   .

Thanks for the help,

Sum

[enjenjo]

Thanks Frank, the HEI is my concern. Are you talking about the fusible link or the wire going to the coil on the passenger compartment side of the firewall??

I seem to have the same voltage at the wire that was hooked to the old coil that I have everywhere else.

I am sure you know that on a GM car, the resistance wire that replaces a ballast resistor is on the engine side of the firewall, going to the coil. On a Ford, it's on the cab side of the firewall, and goes from the ignition switch, to the firewall connector.  As I recall, it has a white woven fiberglass cover.

By it's nature, with a meter the resistance wire will pass 12 volts, because there is little or no load. As the wire heats up with the load from the ignition, the voltage will drop to about 6 to 7 volts.

The engine being a bit lower, and offset,  shouldn't hurt any thing, as long as it's straight in the frame. It may be just a difference in water pump shaft position between the two engines.

We had done a few by the time we had it down to two days.

[river1]

Tomorrow morning I finally get to try driving this thing maybe.  Your 2 day job took me over a month :cry: .  Sum

We had done a few by the time we had it down to two days.

now you tell him    

later jim

[1FATGMC]

By it's nature, with a meter the resistance wire will pass 12 volts, because there is little or no load. As the wire heats up with the load from the ignition, the voltage will drop to about 6 to 7 volts

Ok that makes sense and I wasn't familiar with them since for quite a while I have just had HEI's and was only familiar with the ballast resister setup before.  So I think from what you are saying find the wire out of the ignition switch to what was the coil and just replace it from the ignition switch to the HEI with a normal wire.

The engine being a bit lower, and offset,  shouldn't hurt any thing, as long as it's straight in the frame. It may be just a difference in water pump shaft position between the two engines.

It is higher.  I wondered about the water pump position, but I sold the 390 and don't have it to look at anymore.

Thanks again,

Sum

[enjenjo]

Ok that makes sense and I wasn't familiar with them since for quite a while I have just had HEI's and was only familiar with the ballast resister setup before. So I think from what you are saying find the wire out of the ignition switch to what was the coil and just replace it from the ignition switch to the HEI with a normal wire

That's it.