anybody have any suggestions on how big my gaps should be with stock plugs and 65k coil?

stock spark plugs with a stock points setup & weak 30k volt coil was .035" gap.

But with your 65k volt perf coild i would try .045" plug gap.

scott

What is the gap range of the plugs you're using? Extended gaps often require extended side electrodes.

First Guess: That "65K" coil isn't one bit better than the one that you took off. Especially if this is some eBay/low budget replacement for an HEI coil.

What ignition system do you have? Points? HEI? MSD/Mallory/other aftermarket?

Scott is on the money,
0.045 should be fine
What plugs, Distrib, heat range,wire types and size makes a difference too also, we are just going of what we think you probably have.

I think Tom Mobly gaps his at .055
I heard GM changed the gap size when they switched to HEI back in the 70's to 80's. Most standard increase is .010-.020 increase from the standard .035 . I will do the math for you this time:
.045-.060

Anywere in that range is usually an acceptable increase with an upgraded igintion system, but it all depends on your current setup, .045 may work for me, .060 may work for another cat.

I agree with Scott, I'd try a .045 gap...and then read the plugs and see what you think...

haha schurkey hit it right on, yes i did get the setup off ebay for a low price but i'm positive its better than what i'm running now, which is some mickey mouse points to magnetic conversion kit i did a while back with a 60k coil. i found a HEI distributor with a coil sitting on top thats rated at 65k and has a 5 year warranty, didnt think i could go wrong. i believe the wires are 7 mm, but its been a while, i just remember shelling out a pretty penny for them. i'l give .045 a shot and see what happens. thanks a lot