[Spf79]

I think you will be good on the hwy with the th350, 35's and 3.07's. Probably a bit of a dog around town... but if you are just cruising... who cares?

This has been my experience. I had a 79 k10 swb in college with a 383 built with torque in mind, maybe 350 hp on a good day. I ran this motor with a th350, np205 and a 10 bolt that had 3.07 gears. It had a 4" lift with 33's.

It was not a dog around town, but slower than I liked, between 30 to 50 mph it was quick... IMO. On the hwy, at 70/75 it felt like it had good power and I could get up to 80/85 without much trouble. It had nothing past 85.

That truck liked to cruise at 65, it felt like a small push to get up to 70/75 and maintain. I don't think those tires measured out much past 31/32" even though they were 33's. Thinking about it, if you are looking for nice hwy cruising you might be set up perfectly with the th350 and 35's.

I also had a 74 blazer in high school that had 33" tires that actually measured out to 33 inches... with 4.11 gears and an old dog of a 350. It liked 55, and did not like 65. Based upon that rig I am going with 35s and 4.11 gears because I will be driving around town most of the time, 45mph at the most. If I was going to drive on the hwy a lot I would go with 3.73 OR 3.55's.

I would not stress about the 3.07's, change them when it makes sense to do so. Or keep an eye out for a 3/4 ton set up for cheap. Those normally have 3.73 or 4.11.