28' 1981 Excella- Isuzu Diesel RPM's?

[Jeremy Krug]

I posted this in another spot and it was recommended to me that I post again here:

I recently acquired a 28' 1981 Excella motorhome. It has the original Isuzu 5.9 with 60K miles, when I got it. I've tightened things up and taken two long trips (2K miles each) and I'm hooked!!

It has a replaced tranny (Allison 4-speed AT545). I was running 2600 rpm's at 57mph, getting 12.5-13 mpg. My question is, does anyone know what RPM's this motor is happy with? I'd like to run at 2800-3000 and go 62-65mph from time to time, but don't want to push the motor too hard. Also, anyone have experiences with the Gear Vendor gear splitter? I was considering adding one in the future, mainly so I could tow.

Any advice on this rig and motor would be awesome!

Thanks!
Jeremy

[Magnet18]

I've had a happy experience with the gear vendors unit. Brings the revs down on my 454 to a tolerable level when cruising. Not sure I would pay full price for it, but I'm sure glad the PO did.