Jack 170 is about what I was expecting, or hopeing for. It is a Top loader three speed but I am using second and high only. The driver is having enough trying to do that. In my Stude pickup I have the four speed top loader but I don't know when, if ever, it will be running. I'm thinking of taking my 374 heads to a pro porter to see if he can't do better than me. The car picked up 3 mph between the 2 1/4 and the 3. Have to think about the gears. You wouln't have a junk head I could cut up or one already cut would you. It would help to get an idea of how much is too much.