Not enough gas

I crashed my car 89 shadow, fixed it, and changed my 89 shadow engine to an 89 caravan engine. Well, I ran a race with that stock engine, and then the next week, I put on my shaved 89 shadow head, and put on the caravan throttle body instead of the shadow one, thinking that it would give more gas. Well, turns out that it is actually starving the engine for gas. Could this be something a matter with the throttle body, or something else. I pull the plugs out and they are snow white. Help me pleasE!!

check your fuel pump or fuel filter... possably injectors