New guy, could use advice

[yossarian19]

Hey all,
Been lurking for a little while and scratching my head at what to do. Thought I'd introduce myself a little and ask a few questions.
So, I'm 27 & a mechanic working on EFI cars of course. Living in Oakland, CA and looking forward to moving back to the country. The truck is in Nevada City, my lady's home town, where her brother is patiently keeping it in his driveway. Used to be his dad's, then his, now the girl & I's. The girlfriend and I are taking over the family pickup, a '57 with a blown I-6 (head off, radiator out, #2 crank bearing bad) and wanting to get it back on the road.

As I see it, our options are:

Rebuild the I-6 as best we can, keeping in mind that it is already at maximum bore.
Swap in a carb'ed SBC
Leave it in the driveway for now & save money till we can go LS swap, which could be a *long* time.

The other part -
well, we want to keep it a functional work truck. IFS would be great but my welding skills aren't up to par for that. Looking for front & rear axle swaps that would gain us 4 wheel disc brakes. Any likely candidates that are the right width?
What is the stock WMS to WMS measurement, anyway?

Thanks for any / all help.