[modeleh]

There might be more help regarding Warfords over on the AA club forum. I had always wanted one when I had my AA but could never find one. 30-31 Warfords are supposed to be more common than the 28-29 ones, but I would say any of them is a pretty rare piece, and the couplers needed are even harder to find. You really scored to find a 28 Warford complete mounted in a chassis. I had the 5.14 gears in my 31, but thought 6.6 worm drive was the only choice in 28 so I'm not sure what you mean by you have high speed gears.
I could do 45mph with 5.14 gears no overdrive. I think many AAers overlook the consideration of wheel balance on these rigs. I found it hard to get the truck to run smooth at the higher speeds with such heavy wheel/flap/tube/tire assemblies, and I was running duals on the rear.
Yes the truck can be made to run higher speeds with the overdrive but I think it will take alot of fooling with rim and tire combinations to make the truck pleasant to drive at those speeds.
You may still find 45 is the sweet spot but at least the engine won't have to spin so fast.