I was thinking of the RPM at cruising speed of 65-70 if I can keep it at that speed as I tend to speed a little

I will be running 35" tires on the truck and I figured that my cruising RPM would be about 2450-2500 at 65. I will be running a 91 350 with TBI and the truck will be used mostly for hauling me around, not too much towing or off road use.The truck is my crewcab 69 so I would think it will be pretty heavy and lots of wind resistance no matter what I do. I have a 4L80E and 241 transfer case that I could put in it but I think I am better off staying with the 350 trans and 205 transfer case. Thanks