5x4 Tranny, Spicer ?s

[cable cat]

So I have this mack superliner with an spicer 1252A front box and a 1241C aux. box.

Does anyone have any gear ratio specs on these gear boxes? Reason for the asking

is I have to put rearends in the truck, it had 5.02s in it for toting heavy lowboys and the like.

I have an inkling that the 5.02s are going to be pretty slow for my intended work load, but I also figure

that the 3.86s I have on hand are going to be pretty tall, as well. I dont really want to put a 13 speed

in it to mate up to the 3.86s, so.... for the time being it is getting what I have, but long term I

want to figure up the gear changes for optimum cruise and still retain low end holes for getting out of

field.

Thanks in advance,

cc