1967 rear axle width and backspace question

[kitsbeach]

I'm about to do the 5-lug conversion on my 67 Fleet and wondering if people have an easier time getting the right backspace with the later axles (which I believe are roughly 1 and 1/2' wider or so).

I believe the switch to the wider axle happened half way through 1970.

I'd prefer to stay with most 1967 stuff and I like everything pretty tucked in. I'm planning on running 15x8 steelies on the rear but may go for a taller wheel/low profile tire later for the better handling.

I'd like to have the easiest wheel selection as a lot of rims come with a standard backspace.

My truck has an open (non-posi) 12 bolt with 4.11s. If I keep this rear end I will buy the conversion axles and drums now for about a $300 investment. Then later when I do a V8/LS swap I'll spring for something like an Eaton positraction and the right gearing.

The other choice is to swap in the later 5-lug housing now, but this one works and has new brakes and lines.

Here is a picture from underneath of the wheel in the rear fender well now (fairly tight to frame). I don't know the backspace on the old mags that are on the truck now.