Anyone know what size they are and what they are for on a 71-72 GS (thanx) One on coil .3 or .5 mf not sure for points longevity ? Not needed for HEI switch over ?? one on regulator not sure what size ? for radio noise suppression and point longevity. one on E - Brake mech. to fuse box not sure what it is for or what size it is ?
Try www.lectriclimited.com for reproductions. In general, they are used to suppress the arc otherwise generated when mechanical points open in a transient circuit operating with current. This reduction in the arc both extends the life of the points and suppresses the electric field which is otherwise induced into your radios' audio circuit.
The one on you coil is probably on the "+" side is for AM radio suppression. All of those caps are for either AM radio suppression or to increase the life of electrical contacts like the contacts in your mechanical voltage regulator. You don't need them for HEI but you don't want to run your HEI from the pink wire that goes to the "+" side of you coil since that is a resistor wire and may not handle the current draw of HEI. Find a switched terminal on your fuse box, there's usually one in the lower left side with a 1/4" male spade lug. Crimp a 1/4' female spade lug onto a piece of 16 gauge wire, plug it into the switched lug on the fuse box and run that to the 12V input on you HEI.
If you changed to HEI, the cap on the points goes away. The + side cap should stay, but as pointed out the old ballast resistor must be shorted directly to ignition 12V. An HEI needs a much larger peak current (even though the average is less) to operate correctly. Caps on a gen - reg set would be the same; the exact value of these interference suppression caps isn't critical. An alternator will have its cap inside. Bruce Roe
