63 Panel rear differential

[nadodave]

So I finally drove my 63 Panel the other day - pretty sure it has been off the road for more than 15 year - 13 I know for sure because that is how long I have owned it . It now has a warmed up SBC/700R4 combo, and a 71 disk brake front end. The good news is that it drove surprisingly well. The bad news is that either my 700R4 was not shifting into OD, or I have a felony (numerically) high rear end. The panel was originally a 6 cyl 3 speed combo.
My goal is to have a highway cruiser than can also tow a car trailer, and I am OK with drum brakes in the back. I read in this forum that later rear ends are wider and presumably problematic to install. Questions: 1) Any idea what the stock rear axle ratio is? 2) Can just the gear set be replaced in my differential, and if so, what should I look for, 3) Other ideas?

Also, good ideas on how to troubleshoot the OD issue - other than going to AMMCO?


Thanks