[piecesparts]

To each his own, I have a 700R4 on my 84 GMC with a 383 stroker in front of it. I am running 3.73 gears and about the same diameter of tires. Your setup with the 350 tranny and the 4.10 gears puts you at 3200 RPMs at 70 MPH and 2750 RPMs at 60 MPH. if you run the overdrive tranny, you be basically at 2300 RPM @ 70 MPH and 1930 RPM @ 60 MPH. That should keep you effectively in your power band and not outside the optimum performance level of your engine. Remember that you will have to find a way to control the lockup converter. I am using the B&M lockup controller that reads the speedometer signal and is adjustable for the lock and unlock features.

There are many that prefer the 200R4 to the 700 R4 tranny and they both can be built to handle what you are pushing for power. However, prepare to spend some money to get it done right.