hey hammer, your saying that when you loosen starter that it seems to be ready to go again for a short time,correct? if this is the case sounds like you have a shimming problem and the starter is moving away from the flywheel and if you continue you will mess up the flywheel.Try this as a rule of thumb/ with the starter mounted take you a 1/8 rod or allen wrench and slide between the starter shaft and flywheel this should be a snug fit or close to it.if the clearance is to much shim just the outside of starter if its not enough shim just the inside of stater and if your working a bb you may have to add a gm brace on the back of starter to help keep it in place 2 styles, also make sure your not trying to start the motor with timing to advanced causing it to kick back makeing starter move. wjr