Did you use the same sound deadening pads on the roof? The sticky black tar kind? I put the same in my 69 Camaro on the floor. I heard a lot of complaints about the tar dripping after the car is in the heat. From the time I ordered till I installed, Eastwood came out with a warning not to use overhead. Don't know if you used different stuff, I know they now offer 5 or 6 different kinds.
Mostly done with the new accessory bracket. I really wanted to run a modern AC compressor so I started from scratch and made it work. Still need to source a belt but I don't foresee a problem with that.
That is starting to look like a brand new engine! I am sure you can find a belt. What I do when making a custom drive system like that is to make a "mock up" belt. I take an old belt and cut it. Then I drill a hole in the end, and fasten it back together with wire or cable ties. Then I can keep cutting off more belt little by little until I find it fits the way I want it. After that, it's just a matter of having a store measure the belt you created, and sell you one that length.