225 long rod stroker, HELP

I won't even get into the discussion of benefits/drawbacks of long rods. For a street driver it is not cost effective. Just the rod/piston (K-1/Molner, Wiesco) package will cost about $1100. Stock 198 rods (if you can find a set) should get ARP bolts ($55), and be reconditioned ($150). Pistons would be minimum $160 plus rings. There is nothing wrong with stock rods (reconditioned) and stock type pistons, on a N/A street car.

High stall converters are available with the small pilot, small spline or the large pilot, large spline. It is the "hybrid" (small pilot, large spline) that are getting harder (expensive) to obtain.

I am a fan of the 7 1/4 rear, but parts are getting harder to find, and if not a sure grip prone to breakage, if beating on it. If you are going to change the rear I would go for the 8 1/4, Ford 8.8, or 8 inch Ford, which is almost a bolt in (early v-8 mustang, comet, Falcon, Granada).