fouling spark plugs...

[355shortbed]

ok where to start.. i had a 383 sb chevy built by a friend, teacher , and reputable engine builder last spring through summer. its a pbm kit new roller cam kit from the block up.. around 9.8 to 10.0 compression, aluminum heads a air gap intake and 750 street series quick fuel carb. all around good street motor. problem im having is fouling plugs every week just about. i re-did the drive train in an 84 c-10 to get ready for the stroker. i was with the guy mostly through out the build on the engine and watched it break in and dyno. i believe some where around 410 hp and 475 tq. the motor ran and sounded great in the dyno room and we crated it up and brought it home a day later. i put it in the stepside and got everything hooked up, i took my time as to spending a good deal of money in the truck. i didnt how ever get a new battery at the time i was ready to fire it and it had discharged  so a friend of mine jumped it with his tahoe. got it running and ran great. a few days later was showing my neighbor and the caps blew off the batt due to the voltage regulator frying when jumping, the alternator is a newer chevy 75 amp instead of the o.e. 40 amp. i replaced it and it worked fine. but since then it started fouling plugs religously every week, mostly cylinders 2 and 8. but they all are black but 2 and 8 are wet meaning their shot. spark plugs are ngk 4554's, the truck has been back to him 6 times. and he has replaced the h.e.i. distributor 3 times first 2 were proforms, and last is msd street fire. the truck runs great for about 2 weeks then plugs go again almost like the distibutor is burning out. could the alternator be frying the internals or any ideals.ive tried running a step hotter plug and no change. i run 93 octane ethonol free in it. everything is new underneath the hood so whats up, im stumped., i know theres always bugs but man..  if u need more info on motor and accessories ask. thanks

[Lt.Del]

done a compression test in those cylinders, and compare it to those readings of other cylinders?

[TexasRed]

If it's the same cylinders doing it no matter the distributor, I'd do as SgtDel suggests because it sounds like maybe a valve is too tight. The carb might be fairly rich too.

[355shortbed]

 ill try a compression test my self when i can get a gauge from a friend, i think he may have done one when the truck was at his shop again. it does run rich but what puzzles me is when he put new distrib. in it ran great for 2 weeks or so then plugs began fouling.  the same on both cases of replacing the distribs. funny thing was i tried puting my timing light on and checking the timing and couldnt get the gun to register, thought my gun took a dump and he tried after i hauled truck to his shop he couldnt get a reading with his. he put new internals in old distrib and truck came to life so then he replaced distrib.  like i said did fine for a while then same stuff. last set of plugs i put in lasted 2 days. oh i forgot to mention had to warranty the intake was a proform air gap and it warped and was teeter tottering on block so he put an edelbrock on it, info is info.  he says i should just take it down interstate half hour and run the sh*t out of it but i dont have money anymore for a 300 dollar tow bill to bring it back home   we adjusted the airbleeds in carb up a size maybe thinking it would lean out sum when idling and wouldnt load up so bad. didnt change.  stepped down the jetting in the front and back and ran worse, even tried a 650 holley and no difference. i though maybe just trying a different plug would help but after 3k in spark plugs lol money is geting tight till i leave for basic.

[bowtieman82]

Have you change the wires at all. the problem stay with the same two cylinders with all three distributor. I have a 82 chevy with a 100 amp alternator and i have a distributor out of a 76 chevy with MSD parts and it work just fine. check your wires with a timing light. just move the hook up, up and down the wire your testing to see were the problem is in the wire. and check the ends to see if the are hook up right  You can also test with a volt meter just put the meter on Ohms to see if there is any resistance if there is none the wire is bad.

[TexasRed]

The other thing to check is to make sure the replacement alternator is causing distributor parts to fail.