help pleeze.... running like sh't, now won't start (long)

Reman motor 300 miles on it.... started to drive it to work the other day, in the rain, started missing and generally running like sh't (backfiring, missing, etc..)....

replaced the distributor (bad vacuum adv), started the car, still running like sh't.. backfiring through carb, won't idle (carb was new with rebuild), vacuum leak?? sprayed carb cleaner around base of carb, idle increased... pulled carb, put a thin layer of blue silicone on gasket, re-installed carb.... now the car won't start... does'nt even fire....

no elec meters to check stuff, hooked up timing light, light does'nt show spark (will this work??)...

any ideas???? thinking of replacing the computer and the coil (only as a guess)....

HEELP PLEEZE< any ideas????????????

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84 GT,shorty headers, open dual's, bored .060, 10.5" clutch, T5, 89 heads, edelbrock Performer manifold, matched cam, 600 Holley..