barnett468

hello

it won't hurt to go to 3923 especially based upon how they look, however, you must increase your main jet and check the fuel mix screws.

your rear mains should be at least 1 size larger than the fronts. two sizes larger at the max. two sizes larger is common.

your center electrode is slightly rounded on a few also.

how many miles are on them?


COMPRESSION - what size is your engine?

if it is a 302, you have super low compression. i suspected this when you said you could advance your initial timing so fsar with no prob. if its a 331 it still might be low depending on the head cc.

Gun Jam

it is a 302 with 100+k miles

barnett468

ok

well your plugs look good for an engine with 100k miles. and your compression is pretty low but you would need to mill the heads to raise it so i'm guessing that's out, lol.

Gun Jam

So its not abnormal for plugs to lighten in color as the engine ages?

Thanks for your help.

-Gun