I have a 527cid big block ford peak torque 673 @4400 and 670-675hp 5000-6000rpm. Going in a street/strip car 3000lbs. running a beefed up non lockup AOD through 3.7's on the rear. Top trans guy recommended a 2600-2800 stall converter and Im happy with that, but am now wondering 1. how much slip I am going to get in highway cruise at 70mph @2100? 2. whether that is going to cause heat problems; 3. whether it will cause fuel consumption problems. Like what ballpark mpg approx? I dont care about economy I have one of them, I am trying to work out what fuel tank size is needed to get between gas stations (serious). Would appreciate any comments from those who have similar.