Bextreme04
Full Access Member
- Joined
- May 13, 2019
- Posts
- 4,440
- Reaction score
- 5,581
- Location
- Oregon
- First Name
- Eric
- Truck Year
- 1980
- Truck Model
- K25
- Engine Size
- 350-4bbl
Yep. The lockup is honestly going to be the biggest difference in my mind. The OD gear will make a huge difference on highway driving and will let you cruise much more comfortably for long distances at freeway speeds, but the lockup converter will see efficiency improvements everywhere.Yep. There’s quite a bit of wind tunnel data shows what happens behind the cab with the tailgate closed vs camper shell. The air clears the rear of the truck more cleanly with an empty bed, tailgate shut. Also, camper shells obviously add more weight.
Back to the thread…
Best case swapping in an auto would be anything with a lockup and OD.
How long will it take to recoup the money spent on the swap, in realized gas savings? That’s the question…
The CHEAPEST option is to pull a 4L80 from a wrecked vehicle in the junkyard, put some new fluid in it, make a full manual control for it, and send it.
For ~$50 more, you can get an 0411 computer and pigtails from the same junkyard(often from the same vehicle) and run tach and TPS signals into it from the engine to get automatic shifting. The line pressure will still be maxed out without a MAF sensor input, but you could always wire one of those up too if you wanted to get the full monty. The 0411 will run full line pressure without MAF because it can't get a real torque model without it, so it will just assume max power all the time to protect the trans. You will get firm shifts, but it shouldn't hurt anything.