Mtntopper, Ive changed R&P's and reduction gears to suit what the customer needs. The final ratios are 9.96, 11.24, 13.27, or 14.98. You can figure your road speeds by the dia. of your sprocket. I once set up a Thiokol Spryte A that had a straight axle , steel encased OC-12, with the 14.98 ratio. The customer was hauling huge loads up steep hills and the gearing was not low enough. For this cat I added a 3 speed aux trans between the auto trans and the rear and it gave the low range for climbing, straight though for most work and a high range that gve it a top speed of 35 mph (down hill road). I changed alot of other things on that cat too (another topic). Last time I checked, R&P's cost about $1000 (new if they are still avail.) and a set of 2.44 DB gears are $1500 (used, w/exchange).
mtncrawler, Yes I have seen the chain reduction (I would not have said so otherwise) and had I once had a manual showing it, but right now I don't remember if it was a Spryte or an Imp. I chuckled when you mentioned the spool being reversed for the drop box rears. I ocasionaly get call from folks who rebuilt or had a friend rebuild their rear and they want to know why they now have 3 reverse and 1 forward gear!
Do any of you have a pair of OC-4 drop boxes with the 1.78 gears?
Pat Foster
Wallace Idaho