1991 formula 305, 4speed auto, and stock rear end.

Im building a 383 with a powerband of about 2,500-6,500.
Should I keep the 700r4 with a 4.11 gear or a 3.73 gear?
Or should I scrap the 700and gowith a Turbo 350 or even a 2speed.
Is a powerglide 2 speed with a 4.11 a good Idea?

I was thinking of going 5 speed stick. What gear should i use with the manual?

 

Before you make an actual cam selection your going to have to figure out exactly what your drivetrain will consist of to get maximum results since it all factor in. Tire size is also going to play a factor with overall rpm that you want to be at as well if it's a street/strip, daily, or autocross car. With the OD you can go a little deeper in gears since it will be offset by the od. BUT you may have tractions issues by doing this since overall 1st gear will be a stump pulling ratio. 7004r's are more expensive to rebuild and cost more to make as reliable at higher hp ratings compared to a mildly built TH350. I had a 700r4 done up and a 2800 stall, replaced it with a 350 3500 stall and ran the same number in the 1/4 and crossed at the same rpm so that's something to think about as well, had littlke over $1000 in the 700r4 set up as compared to $450 in the TH350. If going all out on a trans keep in mind a great convertor will generally cost at leat $600 to over $1000 just for that 1 peice. But application will factor into that decsion also. I guess for your 6500 cut off, I'd personally be inclined to keep with a 3.73 so your redline will be in check and hwy drving will also be easier on parts unless your going with the OD unit.