700r4 swap

H

hogcityracer

New member
I have a '78 Scout II with a 345, and 33" tires. I was considering swapping out the trans. For a 700r4. I am a
GM tranny man by trade, so the transmission wouldn't cost me anything, just the adapters.
My question is this, is there a noticeable difference in fuel mileage and performance.
I realize in theory what it should do, but I was wondering if anybody has any real world experience with this swap.

Chip
 
Chip,
Jeff swapped a 700r4 into my build, http://www.forums.IHPartsAmerica.com/IH-only-build-ups/442-pds-drivetrain-upgrade.htm ,and it was definitely money well spent.

I was originally running 35" mtr's with 4.10's behind the trusty 727 tranny. Ran about 2900ish rpm at 60 mph. Currently I'm running the same rpm at 70 mph and rpm's drop to about 2400 at 70 mph with the torque converter locked up. And that is with 4.88's in the diffs. The overdrive and the lockup tq converter have made a world of difference.

I can't really give you good comparison numbers on mpg between the two different set ups because with the xmsn conversion I also went to a throttle body f.I. I usually cruise down the highway around 75 mph (70mph speed limit out here in tn) and I'm getting 12-13 mpg on average. One of these days I'll take my foot off the skinny pedal and see if I can do a little better.
 
Thanks paul,

that's exactly what I wanted to know. I'm also converting to fuel injection, so that gives me a pretty good idea. I think I'll give this a shot.

Chip
 
How does the kick-down linkage work, I'm considering going to and auto from a manual. Who knows what adapters are needed, I also have a 23 spline atlas that would require and adapter also. Thanks
 
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