Unless it's too late, you might want to consider building your FED to work with 31" tall tires. I have talked to a number of racers that wished they built the car to run shorter tires, and not have clearance problems. With your motor back at 39" and the 33" tires you could dead-hook, there by pulling the motor down below it's HP rpm range.
Our motor is at 48" running an all iron SBC on alky in NHRA Heritage JrFuel running 7.0's at 189mph. The light weight [ 22.6 lbs] GoodYear 31x12x15 tires allow us to keep tire speed up and rpm up to where they are both happy.
The farther back the motor is and the shorter the wheelbase the more weight you have on the rear slicks, which equal more traction, but it could work-out to be too much traction, unless you race at a lot of crappy traction tracks.
Good Luck with your FED project.
Feel free to call me if you'd like to "brain storm", 805-444-4489
Jon Hansen, Hayden Wheels