- Joined
- Aug 29, 2010
- Posts
- 47,210
- Reaction score
- 9,482
- Location
- OKC, OK
- First Name
- HotRod
- Truck Year
- 85 K20 LWB
- Truck Model
- Silverado
- Engine Size
- 454 - Turbo 400 - 3.73
I generally use D at 50 and below, or up to about 60 if it's a bit hilly. But on level ground, I get better highway mileage in OD. It's currently 33's and 3.73. Stock was 235/75's with 3.42's, but it had 31's on it when I got it. Well, they were called 31's but they measured smaller than 30".
Yep, they are just under 30 sitting in the driveway, but being a Radial tire that grows with centrifical force, its probably 31 by the time you get to about 35-40mph.
So is this a carbed motor? You have so damn many trucks, I don't which one were talking about. Sometimes you can be going about things the wrong way. You know the CC lock up is controlled by a Vac switch if its not TBI. If you were to make some changes to your motor to increase mid range power, and the motor didn't strain and lose vacuum, you woudln't have this CC lock up in and out near as much. I really wish someone would invent that vac switch to be adjustable like they are the vac modualtor on Th350 and Th400's. That's not to say thogh, that you still passing that strain onto the trans. Honestly though, I think an RV cam would increase low to mid range power where you're not putting as much strain on the motor at mid range, therefore the vac drop woudln't be enough to shut off the lock up feature, keeping the trans cooler and in the long run, cooler trans equates to longevity.