I have a '72 350 with an add on HEI. I had the plug wires removed (and marked) and misplaced them over the summer. I had to buy new wires and need to know where the wires go on the distributor cap. I know the firing order on the engine but do not know where to put the wires on the cap. The electrical block on the HEI is pointed towards the driver's side fender. Any help would be much appreciated.

 

Technically the wires can go anywhere on the cap as long as it goes in the firing order. As long as you did not remove the distributor and the engine was in time before you took off the cap, just put the engine on T.D.C. on the compression stroke and see where the rotor is in relation to the cap. Mark that as #1 and then connect the following wires going off of the firing order, making sure you are going the direction the rotor normally turns.

 

Looking at the distributor from the front of the car # 1 cylinder is in the 5 o'clock position then in a counterclockwise rotation #8-#4-#3-#6-#5-#7-#2

 

Easy,
start directly behind the coil pack on the dist cap. Looking from the front of the car to the back the #8 plug is at the very back left (same side as the voltage regulator), the next one to it's left is #4 then #3 etc. That gives you the right order and the directional turn you need to fire properly. (Olds distributor turns to the left). When you're done, #1 is just to the right side of where you started #8. I drew a picture on the computer to show you what I mean. It's attached to this thread.

One more thing, now that you have an HEI distributor, a standard air cleaner won't fit. You'll have to adapt yours, or get one with clearance for the HEI cap.

 

One note on the air cleaner. Years ago when I put the HEI on my 72 Cutlass, I bought a plastic spacer that went between the carb (Q-Jet) and the air cleaner. It was so long ago that Super Shops was still in business. I think Holley made it. It easily cleared the hood and the only thing I had to do was use some fex for the stove pipe. I don't know if they are still available but it was easier than reworking the air cleaner and looked better.