Brown lipe 5057

[cerial]

I have a 3 speed brownie with a side rails(not top)case that looks similar to model 31-37. But it has 5057 cast into the case and 5117 on the large cover.
31
But the thing has straight cut gears which have same 1.52,1, .72 ratios as the the 5831.

Did this thing come with these gears?
Anyone have info what this was behind.
I believe the 58xx were in the 450/470 series and 3xx were in the 400.

I want to put the thing behind a sm465 and engine making around 330lbs. In front of a 10 spline np205.

If a 305 v6/sm420 was in front of it then were in business. Thats what i planned on.

If something else I will need to think things over.