[mr48chev]

For your gasser look plans and the performance angle I'd have to go with the 472. More tire frying power than you can use with any degree of sanity but so very easy to live with when you are just driving. You may want something up in the 3.3 or 3.5 range gear wise though. You may have to figure out the exhaust clearance or run headers but that should be a straight forward installation otherwise.

The 283 would be a bolt in after you got a V8 truck bellhousing to mount to the crossmember and if the truck was already a standard shift truck. They are cute little motors that have a great following and can be built up pretty well but even a stout 283 won't have the power and torque of the 472 and it will have to work a lot harder to produce that power.

The other thing is, and it's none of the business of the rest of us, what will your budget handle. Installing the 472 you already have if it is in good shape and the trans is in good shape and being ready to go or buying, most likely completely rebuilding and then buying speed goodies for the 283? The 283 is most likely a 2 barrel engine so a head change, probably a bore job with new pistons, new cam and lifters and the right intake and carb all have to be added in to that almost cheap starting price. You do end up with a nice looking and sounding engine that is easy to find the add on parts for though. Things like valve covers, headers and other "gasser' pieces are very easy to find and usually fairly inexpensive.

The other thing is that if you know the 472 is good you could sell it to finance a good portion of the redo on the 283.