8-3/4" Purchase Questions

Lets look at all of them

Option #1... If you do this make sure it's a straight housing before you even bother welding perches back on. If the guy that cut the perches off got "torch happy" it's possible he warped the axle tubes. If it is straight, weld the perches on slowly. Do 1/2 to 3/4 inch welds at a time alternating from side to side. It's a lot easier to warp a housing than a lot of guys think.

Option #2 may have small bolt pattern axles but if I read it right it's a complete axle for $250? If it is complete it's a great buy as long as it's in decent condition.

Option #3 The 742 case was last produced in late 68/early 69 so there's no way it's original and who knows what it really is until you measure it. I've seen guys spread springs an all kinds of crap to make a rearend fit. If you verify it is a complete earlier C-body axle assy swapped into the 77 it can be narrowed but that'll be another $250-450 depending on labor costs where you live. Even if it costs more it has the advantage of larger brake assemblies than an A-body rearend and big bolt pattern wheels if that's what you prefer but more than likely you'd be able to find a A-body rear ready to go cheaper than it'd cost to build this one.

BTW: not a huge deal to me but you'll rile a lot of Mopar guys saying you want a "posi". Posi is a GM only term. Sure grip is the Mopar term for a limited slip differential.