Used this on a 455 Olds motor with headers. Tons of clearence! Would start up just fine if cool. Drive the car for 5 minutes and shut off and try to start again and its heat soaked. Will not turn over fast enough to start. I then put a heat sheild on it. Same problem. I put the old original big bulky starter back on and NO PROBLEMS...starts everytime! So now I have 185 dollar starter sitting on my bench that I wasted money on. I will not recommend Tuff Stuff to anyone!