HEI ???

[77cruiser]

Friend of mine has 2 55 Chevys, converted to HEI. One keeps burning up modules the other keeps burning center contact to the coil.
Is this a voltage issue? I think he's just has it hooked to the original ignition switch.

[rgalajda]

The best HEI module is the ac delco 990 from yesteryears . You can find it in old HEI distributors. I save all of these. These new ( china ) HEI distributors come with less than adequate module which soon burn out.
The module must be installed with a good heat transfer paste. I use Heatsink compound, as used in computers (clean the surface first). Easily available at a computer store. Not Dielectric grease, best not to trust some package of grease someone hands you.
I believe the AC Delco D1906 is the new replacement for the 990 module.
Gap the plugs at around .035" for best performance.

The positive feed to the HEI needs to be a #12 wire minimum .

Last time I saw the centre contact burn was with a MSD system hooked to an HEI.

[77cruiser]

Never asked what he was using for modules, probably part store ones.

[Papastoy72]

Check to make sure distributor is well grounded. HEI's obtain their ground thru the hold-down clamp. Many times, this clamp is either painted or anodized(aftermarket) and does not make good connection with the intake manifold. Also make sure the intake manifold is clean to bare metal at the point the hold-down clamp touches.

[rgalajda]

[77cruiser]

I misunderstood him, the one car is burning off the power wire to the coil. Hope I got it right now.

[Papastoy72]

[rgalajda]

[77cruiser]

Positive to coil.