NEED OPINON ASAP on new bus

Bus dad · 08-30-2013, 06:01 AM

We currently have a 36 ft TC 2000 Front engine wiht a 545 and 4.38 rear end. Mileage is 10-13 depending n speed ( rpm) 55- 13 65 -10. We max out at 68-70 ( flat nose wind dependent) We are planning on buying a pusher next week but it is a high ceiling 40ft with a newer 5.9 (not isb) with a 643 and 4.78 rear end.
Can anyone tell what speed/mpg to expect form a 40 foot BB Rear with a 5.9 643 tranny and a 4.78 rear end. We will be driving it back from out west.
I am having concerns since I have read some post where this rear end they had the tach buried to go 62. But I did not know that "posts" tranny.
Will the 643 get better mpg/speed than the 545 even though they are both 1:1 since it is lockup

What kind of mileage with this config @ 55-60????

opus · 08-30-2013, 10:25 AM

Shooting from the hip; I dont think you are going to do as well as the bus you are replacing for mpg or speed. The 643 is however a huge improvement.

You are adding height and length, which is weight and resistance.

crazycal · 08-30-2013, 09:39 PM

Every bus is different even with the same specs. I doubt the tach would be pegged with a MT643 and a 4.78 rearend @ 62 mph. The 643 is way better than a 545 on the freeway.

Motobus · 08-31-2013, 12:14 AM

Is the tire size the same?

Bus dad · 08-31-2013, 08:11 AM

Wow what a last 24 hrs. We looked at 40 in Detroit and realized to long. As a long shot we happen to look at inter w 466e and 5speed md3060. Now get this it was geared to do 65 @ 1650 rpm. It did have some rust. It drove better than bb, turned sharper and quieter. I know most like bb. I was a die hard 5.9 guy but to get a world tran 1650 rpm for 3500 with some rust. Any opinion on 2001 int amtran w 466e

opus · 08-31-2013, 11:32 AM

The DT is a great engine! Economy won't be as good as a Cummins but I wouldn't let that turn you away. Can't comment on the amtran part, those were after my skoolie service days.
That's a nice gearing setup.

bansil · 08-31-2013, 06:12 PM

Any tranny is better than the slip-o-matic 545....466 is a sleeved engine correct,which means you can do an in frame.....
Mileage I don't think will be different....but! I "think" jakes can be added to the 466...am I right?