I have been having problems when i step on the gas. Sometimes i can press the pedal to the floor and it will take me like 30 seconds to get up to about 40mph. It is just really slow sometimes, but then the next thing i know, it works fine....any thoughts??? Sorry, i am new at this stuff and don't know much about engines.... i'm not even sure what kind of engine i have....any ideas on where to find casting numbers? I have no papers on it. 85 k5 blazer with an old 305....must have more power!