700r4 and 5.14 gear ratio

[fjmiii327]

Hello, I need an opinion out there. I have a 72 chevy K20 stock 350 with
700R4, NP241, 4.11 rear , and 33 inch tires. The setup is fine except it needs more power when towing trailer or hauling heavy load.

I am only interested in re gearing my old eaton axle that I want to keep and I would go with 4.56 but I can only get 5.14 right now. I am wondering if that will be okay with the 700? 65mph at about 2380rpmm in overdrive is acceptable correct? I am concern about the 700s low first gear (3.06) with 5.14. Not too deep? Will the tranny be able to shift normally and not out of whack?

Thanks.

[raycow]

I don't see any problem with an excessively low starting gear. If you had a manual 4 speed it could have a 1st gear ratio of 6 or 7 to 1. The 700R4 will continue to shift normally at the same engine speed as before, but the shifts will occur at approximately 20% lower actual road speed. If this is not to your liking, you could go inside and diddle with the governor to raise the shift points.

2380 rpm at 65 mph is what I come up with too. To get the speedo reading correctly will need to replace the speedo drive gears or use a ratio adaptor if you are outside the range of available gears (3140 driveshaft revs/mile).

Ray

[fjmiii327]

That is what I thought too. Thanks Ray.