12 Bolt 3.54/3.55

[Wide Open]

Beat me to it! I was going to say the same thing.

I think we are talking mpg's while the OP is talking about responsiveness. He stated his setup has too long of legs not that his mileage is bad. Which it probably is considering it's a truck with a big block

[AnotherWs6]

^^^^Probably talking about both. He did mention that he has seen no improvement in MPG with the addition of OD.

[Howitzer]

I was concerned with the "long legs" because my MPG is crap, no change from the TH400. I should have seen some improvement, hence the gear ratio change to something numerically higher. Anybody else running a big block wth a 700R4? What do you have and what are you getting?

[Wide Open]

Originally Posted by AnotherWs6

^^^^Probably talking about both. He did mention that he has seen no improvement in MPG with the addition of OD.

Yep. Missed it.

[Wide Open]

Originally Posted by Howitzer

I was concerned with the "long legs" because my MPG is crap, no change from the TH400. I should have seen some improvement, hence the gear ratio change to something numerically higher. Anybody else running a big block wth a 700R4? What do you have and what are you getting?

I don't have any big blocks currently but I've had four previously. All 454's. One with an NV4500, two with 4L80E's and one with a 700R4. The two with the 4L80E were fuel injected. One with 4.10's the other with 3.73's. Both 12 mpg's around town and the 3.73's just over 15 highway while the 4.10's never got better than 14.7.

The NV4500 did a best of 15.5 highway unloaded it was also 4.10's.
700R4 with 3.73's was mid14's.
All had roughly the same tire size of about 30"

My cousin had a 72 C10 wth a factory 402/TH400 that got 12 no matter what. Don't remember the tire size and no idea the gear. He traded it for a 89 dually with 454/TH400 that I think had 4.10's and also got 12 no matter what he was doing.