I know it's a bad idea to start another ratio thread but I couldn't find an answer to my question by searching the other posts.

OK so here it is - I have a 3.56 open RE in the truck now and a 3.07 open RE I bought thinking I would swap it and get better mileage. I know that if I did any towing or pulled a grade I'd lockout OD but I live on the flat and rarely go out of the valley. I know it would be like having a double OD since there is about 16% difference but when fuel prices go back up it might be nice.

The heaviest thing I'll be towing is a 20ft bass buggy up a few grades not much over 7,000 ft or a trailer not more then 5k. Phx to Seattle and back.

I've read that parts are hard to come by for 3.07's and was wondering if it's worth the grief ?

Is anyone running 3.07's with a slush box ???

 

I've heard of a few people that have 3.07's with a 518. They seemed to like it, and one guy towed around 7K with that set up and said it did fine. I say go for it.

 

I have the 3.07s with the 3 speed 727. It will tow what ever I have hooked to. The original owner bought it and hauled his 5th wheel coast to coast and up and down the eastern seaboard. I assume the 1st 2nd 3rd ratios are the same in the 518 as in the 727. Only diff is you have 1 more gear. I don't tow anymore with my 89 due to egt issues ( play truck now ). I used to hold in second gear if I was at 45 or lower on in town roads. I had another stock 89 that I towed my 7500 pound tractor plus the 2000 pound trailer. I must have been around 10,000 payload all together with tools and weights. It did just fine. Off the line was a little slow but once moving it was fine.