Does anyone know if the 64 and earlier 4 speed trannys had a higher 4th gear ratio than 3d gear in the 3 speed colum shift trucks? I have the 3 speed trans with the 223 and low rear end gears (3.90 I think) so I'm looking for a bolt-in improvement for highway cruising. Will that early 4 speed bolt up to my 61 bellhousing? Thanks!

Kris in Georgia

 

Nope. Both are a 1:1 top gear. I think adaptors are available for the AOD, or you can put in higher gears, with a granny low tranny.

Jared

 

Thanks Jared - I think I've just decided to simplify things and swap out my ring and pinion. I would be very interested in that AOD adapter though if you know of a source. I talked to Advance adaptors and called a few places but no luck.

Anyway if I change my rear gears, I know I'll lose a little off-the-line grunt but it'll help it cruise a little better. Based on my calculations, at 70mph with my current 3.90 rear gear and 235/75/15 tires, I'd be turning about 3174RPM - which in that six is screaming. A 3.50 gear would take me down to about 2848 and the 3.25 to 2645. I don't think I'd go much higher than the 3.25 and I might be able to live with the 3.50. I DO love that kick in the pants when you take off.

Kris