63 Nova Tubbed

I want to tub my 63 Nova without buying any pre fab parts. The final outcome is to have some N50-15 in the wheelwells. I probably wont put a lot of horsepower through it. I have a shop and some metal fab equipment, welders etc. I looked at it closely and would like to do it this way . Remove the tank and carefully cut out the two frame rails and move them in 6 inches and tack them back in. Make are cross rail at the front perches and that loops the driveshaft and to reposition the front leaf mounts. Somewhat the same in the rear but the rails will have the holes and bushing is them already. Narrow a Ford 9" by cutting the axel tubes at a midpoint removing as required and rewelding. Get the axels resplined by a pro. Move the spring purches in to fit the narrowed spring width. Or find a diff that may fit and work without that expense. Cut and widen the wheelwells, removing some of the trunk where nessessary. If anybody has done this or a similar method with the same results. Without spending a lot please get back to me.