Unless your towing ALL the time, 4.56s will give you the best power to economy with 35s.
I did the SAS on my truck and kept the 3.73s when I put 35s on it. It was still a 700R4 back then, and it was OK but I only towed on occasion and when I did it wasn't fun.
Then I bought my 19' camp trailer. At that point I had installed a NV4500 but still had 3.73s. It was a struggle with the trailer being such a wind drag. Headwinds were a solid 40MPH, same with hills.
After a few months I went to 4.56s. It helped a good deal all around, trailer towed better could usually keep 55MPH up hills and in winds no problem. At that point it was the motor lacking power, not gearing. The truck and trailer together weighted just a smidge under 10k.
Swapped in a mildly built 454. As it sits now, truck and trailer with quads and tongue extension weigh in around 12k. With my gearing I can keep 75MPH no problem, 60 in headwinds and up steep hills, all while maintaining 9.2MPG.
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