i have a 94 z28 with a forger 355 the compression is about 12.0:1 i have ngk tr6 and their gapped at .35 should the gap be opened up it currently pops through the exhaust on decel and has a slight miss unles your in it hard it goes away?...any suggestions....when i first got the motor back together the 6 and 8 plug wires were switched maybe fouled a plug?

 

i was told that the smaller the gap the easier it is on an opti with high compression, but i had NGK in mine and they fouled out faster than i could imagine. it would clear out under WOT but begin to bog down again once i was at cruising speeds

 

The NGK specs call for 0.035 gap for that plug, which is one heat range
colder than stock, which is designed for high-compression engines. You
might want to yank the plugs, read them, clean, and re-gap them and
maybe, check the OHMS on the wires.

Is this a recent rebuild? How long has the 355 been in the car since the
rebuild? And the plugs and wires and opti?

 

about 350 miles

 

I just installed new TR6's set at .035" and they seem to work well so far. I'm running a bit over 12:1 and have an MSD D-6.