OK, been reading through old posts, but didn't find what I was looking for.

What is the proper gap for plugs if you are running a Mallory Unilite distributor and Mallory Promaster Coil?

I know HEI is wide (.045-.060) and points are small (.030-035), but what am I running? MOre like points, or more like HEI?

Is the Mallory Unilite considered an HEI ignition since it is not points? Or is the Mallory system more like points since it uses a ballast resistor to reduce the volts from 12v to 9v going into the coil?

Thanks for any advise.

Mallory's instructions say use stock gap for street applications and to start with street gap and make small changes as necessary for race applications.

So, is that stock gap for an HEI system, or stock gap for a points system?

I hesitate to get in on this one, but just can't help it.
Let me ask what spark plug you are going to use. Reason is, if you are using an R43S or R44S, they are intended for (around) a .035 gap. If you stretch it too far, then the ground electrode will not be parallel with the hot one and you will give up efficiency. If you are using a platinum tip, dual electrode, or AC Rapid fire plug, you wont want to disturb the gap either, for fear of damage to the tip.
Old school is that it will only take the required voltage from the coil to jump the gap. In other words, if you've got a coil that puts out 40kv, yet it needs only 15kv to jump the gap, thats essentially what you'll get.
More old school...a wider gap will create a hotter spark.
So. I've said a little that may very well stir up a lot, but still haven't answered you question.
Here is what I'm doing and am actually right in the middle of it. I had been running an MSD 6AL box and their blaster coil, triggered by my old faithful (& modified)Accel dual point distributor. JUST DID drop an MSD billet distributor in it. In fact, I know it'll run (well), but had to get a tach adapter to operate the hood tach. I know that now works too, but have to get the wires cleaned up before I drive it any more. I am using #7 Rapid fire plugs and all I did was make sure the gap and alignment was good. Left the gap where it was.
If I weren't using those plugs, I would start with a set of R43S and gap them at .035-.038" and check them after 500 miles or at least a couple of good runs. If they're fueled up, I would at that time attempt a plug DESIGNED for a wider gap. This would be like an R43SX (or R44SX) and put them, most likely at .060". Then pull them and compare.
All the time keeping in mind if they ARE fueled up, it may be carburetion...Also keeping in mind that if you are running tight on clearance in the combustion chambers extending the gap too far may not be ALL good. I don't believe this would be an issue, but....
Good luck.
Greg

LOL, How stupid would I seem if I just said I bought AcDelco plugs for the smaller '77 6X-4 plugs holes, and the plugs are painted on the sides with "AcDelco" and then a number "2" down and to the right of the word.



Good post though, but no idea on what plugs I have.

Well let me ask you this!
How stupid would it be for me (or anyone) making a suggesting without first qualifying just what you HAVE?
Anyhoo, I'll say what you got is going to be an AC DELCO #2 Rapidfire plug with a special tip that is gapped at the factory at .045". and should not be jacked with, excepting defects or something of that nature...Otherwise, same rules apply only the conventional plug is most likely an R45TSX that gap at .060". These seat (tapered) differently than the numbers I mentioned in my earlier post that are plugs that use a gasket to seal. As I know it, the 6X heads wont offer any clearance issue as they have big chambers. At least the ones I'm familiar with.