I am in the prcess of rebuilding the 8" rear in my 66 fastback. I have a set of 3:50 gears in now but am considering going to a 3:80 or 4:11 ratio. The engine is a 289 with 10:1 comp 220 cam edlelbrock heads and rpm intake with 1 5/8 headers and a t5 tranny. I put the 3:50 gears in when I had a 4 speed in the car but now that I have overdrive it seems like I should go with more gear. What do you think is the best gear to run with this combo?