how much plug gap?
 

i have a 13 to 1 compression open chamber 468 bbc,with msd 7al3 ignition on race gas in drag car ,i was wondering what the best plug gap and timing might be?dont know if it matters but heads are aluminum.

.030 will work fine.

X2 .030

start at 31 degrees total timing then make a pass.step up to 33 degrees make a pass.if it went faster add more../...its really what ever makes your car run the fastest with the least amount of timing in her is goal

Whoops, didnt see the timing question.

I run 40 TT in my 13-1 cast iron headed 496 bbc, every combo different.

I agree with russ, start out low (around 33/35) and gradually work your way up.

Goodluck, Cp

as said .030 on the gap
Mine runs best around 38 deg but never been on a dyno.

timing
 

i was running 35 total car was running 6.40 went to 38 total car went 6.33 i think i am going to try 40?