I Need Help

I am just suffering problem after problem with my car. 91 race built engine in 95 GSX. I was driving today, launched and got into boost and then settling down to cruise speed the car started missing, rpm's going down while driving, the car bucked a couple of times. I pulled over turned off engine. Checked engine, timing marks the same so timing belt did not move, checked axles thinking I broke one, its fine. Turned engine on and runs fine. So I am close to destination and got into boost again a little and slowed down to intersection, turned and she dies on me. Pulled into station which I was lucky was close. Started engine agian and she turns over and runs, oil pressure good, but she just shakes over and over, the engine. Towed the car back home. Put in new spark plugs thinking the other ones fouled. The spark plugs definetly fouled and look terrible. I was using autolite 63 and never had problem when using 92 octane, but ever since using c16 have had problems. Finally got the BPR7ES NGK today after ordered 3 days ago and threw them in thinking the spark plugs are fouled so this is the problem. Same problem, It starts, but engine runs and just shakes. What is going on? I have crankwalked a 2g engine and rod knocked a fully built 2g engine years ago before and when that happend all check engine lights came on and it sounded like metal hiting metal, but this is different. Now I have fully built 1g engine. Any ideas of course of action. I am afraid to start engine again. I think I internally did damage. Definetly fouled the shitty autolite plugs, but replaced them with NGK new ones and still engine just shakes and rpm says .25 or almost no rpm. Any help or response will be appreciated.