For what it is worth, almost all of your questions can be answered and sources provided if you can find a paperback book entitled

"How to Build a HOT ROD Model A Ford" by Dennis Parks, published by MBI Publishing Corp. of www.motorbooks.com,

That whole book is a complete build up of exactly the same model you have and includes instructions for chopping the top and installing things like an air conditioner, although the book does use a lot of top dollar parts. It does show a Chevy SBC, I wonder why? In spite of folks on this Forum having their favorites, there is a good reason why the SBC is so popular in a Model A. I love that high revving 289/302 but you will need a special aftermarket short water pump. On the other hand I have almost $300 extra in a gadget to raise the fan up in the radiator space on my Model A so that is a trade off. The flathead looks easy until you try to find a good one or try to repair a block that has cracks or needs sleeves. Be warned that you can build a SBC for under $2000 while a flathead or Chrysler hemi will be more than twice that amount and you can get as much H.P. from the SBC easily. Anyway the book by Dennis Parks is excellent and will guide you through the necessary steps in the right way. While a top chop looks great (to me) and looks to be easy on these squarish bodies, once you cut that top off someone will have to come up with good welding skills to get it back together. I would think any large book store should be able to get the Dennis Parks for you.

Don Shillady
Retired Scientist/teen rodder