Plug gap with hei?

[j20brett]

What spark plug gap are you running with an hei setup? I reset mine from .035 to .045 the other day and was curious what everyone else was doing.

[billyrb]

I usually run anywhere from .05 to .06 depending on brand and their recommendations.

[qtrac82]

GAP

What spark plug gap are you running with an hei setup? I reset mine from .035 to .045 the other day and was curious what everyone else was doing.

Depends on coil output too. With a stock GM HEI unit with 35,000 volts gap is .040-.045. With a better unit like a DUI or Ford with 40,000+ volts
a gap of .050-.055 is about all you need.

[j20brett]

This unit has a 50,000 volt coil...guess ill bump up the gap again.

[710 Burner]

A typical Chevrolet with a 350 engine used R45TS plugs gapped at .045 from '76 through at least '84. Ford's recommended plug gap was .042-.046 on nearly all of their V8's. Some late 70's to early '80's Oldsmobiles had a .060 gap

[jeepsr4ever]

.043-.045

[etjeep]

I opened mine up to 0.045 when I went to mpfi and a hot coil, but I think it was already said stock gap is 0.035 to 0.045.

[pb]

I found with my setup .043 works great.

[Dr.E]

Plug Gap

Just remember electron flow is in the path of least resistance!
The rest of ignition system must be up to the task.
I proved that to myself by running too large of a gap.
The coil arced to the neg pole and burnt thru the coil tower.
I wouldn't have believed it if I didn't see it. (BlasterII coil/MSD 6al box+ MSD Super Conductor wires).....(.055 gap)
All you need is a reliable arc, proper AFR, &timing=explosion.
Many including myself have chased our tail
when one of the above
has been assumed correct.
My latest assumed ignition problem(tail chase) turned out to be a combination of a slightly rich AFR
at idle and too much initial advance.
I hate intermittant misfires!