I did a search and alot of people seem to recommend gapping plugs at .035. Recently I purchased a set of Autilite XPPerformance plugs and they are gapped at .045. Is it safe to gap mine at .035 on my 305? I want to achieve the most optimal spark here. Just to let you know, I have brand new MSD distrib with blaster coil and MSD 8.5mm wires.

Also, I have no idea what I'm supposed to torque these plugs to in my engine. I'm trying to do the install tonight so if anyone can help that would be great.

 

with more spark power (bigger coil) you can run a larger gap and get more power. (basically). That's without looking at compression ratio, boost, quality of gas, altitude, etc etc
I think you're not at the time to think about those yet... .045" is a good safe bet.

I've never used a torque wrench for those, just go finger tight plus 1/4 turn or whatever it says on the pack. Depends on the bevel after the threads.

 

Thanks for the quick reply. I do want to optimize this as much as possible, what do you think I can increase the gap to without going overboard?

 

I ran a factory spec gap on the HVC ignition. That was on my old engine, though...

 

If anyone knows the actual torque values, it would be great if you could share. I would prefer to torque these to spec.

 

Got all the plugs installed, hand tightened and turned to between 1/4 - 1/2. Car fired up right away and runs even better than before! I love these Autolite XPPerformance plugs.

 

On plug gap according to the Jacob's performance book,and I've tried it,you can try opening up the gap .005" at a time until you feel it flatten out under load.It's trial and error and takes some time,similar to indexing plugs,but it does help.Like Sonix said .045" is safe and that's the rule of thumb on plug tightening,book says 11->15ft/lbs and don't forget the anti-seize.During the '70s factories were using plug gaps up to .065".With the MSD 8.5's and coil you could go .050 to .055 I would feel certain.Just make certain you have full 12vdc running your coil.