my engine was running super lean for a while (plug tips white). the car would run fine on normal driving but would backfire out of the exhaust whenver I got on it.

I fixed the running lean issue (didnt change the plugs though) and it started running prefectly. I changed the coil at the same time also. I checked the plugs after a day of driving aroung and part of the plug was a nice brownish color and the rest of the plug was still white. I left them in since it was running so good.

Anyway, the car was running perfeclty for the last week or so then tonight it started surging a little bit while I was on the freeway and when I got on it it started popping out of the exhaust again.

I can find no vacuum leaks, the plugs wires are in good shape and in the correct locations...I am just hoping the plugs got jacked up when it was running super lean, cause I am sick of this issue!!! I am going to pick up some new plugs tomorrow.

here are the specs:
383 10 to 1 cr
lunati 60302 cam
edelbrock heads
TTI 1 7/8 headers
rpm performer intake
670 street avenger
MSD ready to distributor
Denso alternator swap
stock coil on there now
using champion RC12YC gapped at 35

THanks for any help or ideas.
initial timing at 18 total at 38 in by 2500