Bunch of Noob question from a Dutchman
The stock stall changes my cam pick a bit. The stock stall in those big passenger cars was a low stall unit, and that coupled with a too large cam can make for a dog off the line. If you are definitly keeping the low stall, I could recommend the factory 440 magnum grind cam. It works well. As far as the 8-3/4" rear, it could have any gears from 2.76 to 4.10's or even lower in stock form, depending on what it came out of. If the tag on the rear is missing, you will have to manually check the ratio. For a street cruiser with the stock stall, I would look for 3.23's or 3.55's.