You don't need a blanket because if you have a KB/B1 with 1200 HP you need to be using a heavy case anyway. You might need to use a starter without the outboard support for the drive. I used a Meziere on my hemi for clearance but those things are so good you would want one anyway. My buddy has a glide in his Dart, he had to modify the trans mount but it wasn't a big deal, just some fabrication. Your crank situation is unique but hopefully you can put the powerglide adapter with what you are using now and make it work. A 1.80 straight cut is the default low gear set. I love 727's but at your power level you will probably prefer the glide.