converting an 8 3/4 to the correct sure-grip

So I'm converting my '65 Dart GT 7 1/4 to the 8 3/4 rear-end which I found months ago. After learning late and reading lots I see that "bolts right up" is not true and the correct "sure-grip" conversion set up has many combinations of right or wrong pieces that has to be chosen now if I don't want all the headaches you guys tell of. Example: the 4-12-10 thread by member 71 DUSTAR, titled 'axle lengths for 8 3/4' scared me straight that I need to learn quick about the variables that could create friction and driveline failure and if I was to listen to my local Mopar wrench buddy who says " bolt it in, it'll work" I could get hurt. In the Dodge '65 Dart-Coronet Tech. Serv. Manual on page 3-15 titled 'Rear Axle-General Info, it states 'The Dart model cars are equipped with a conventional type diff., however a Sure Grip diff. similar to those used in the Coronet model cars is available.' 'Refer to the Sure Grip Diff. section of the axle group for the serv. proced.'
This is the last part of my power-train resto. that's left and I want to make it correct as possible before the huge body-interior project ahead. In the recent thread by 71 DUSTAR it mentioned one of 'several Sure Grip packages' to choose from? What the heck? Simply put, is there a specialty shop that I should turn this over to that knows everything about making this rear-end the perfect Sure Grip that's highway geared and ready to bolt on? I don't trust the "this will work" feedback I'm hearing from my buds.