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**Captainfab** · 08-15-2011, 12:52 AM

I wouldn't bother with switching from 4.11's to 3.90's. There really isn't anything to be gained. If you decide to go with the 396/TH400, I would change the rear gears to a 3.08. The BB will have enough torque to pull the taller gear, and it will be more highway friendly. If you stay with the I6, and install the 700R4, I would suggest a 3.42 rear gear. The lower 1st gear of the 700R4 will help get moving with the I6, and you will have a nice low highway cruise rpm in OD. Of course this is dependent on your selected tire size.

08-15-2011, 12:52 AM	#12
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,254	Re: Still up in the air.... I wouldn't bother with switching from 4.11's to 3.90's. There really isn't anything to be gained. If you decide to go with the 396/TH400, I would change the rear gears to a 3.08. The BB will have enough torque to pull the taller gear, and it will be more highway friendly. If you stay with the I6, and install the 700R4, I would suggest a 3.42 rear gear. The lower 1st gear of the 700R4 will help get moving with the I6, and you will have a nice low highway cruise rpm in OD. Of course this is dependent on your selected tire size. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE