Newb Questions

I’ve been reading around on a 360 swap and have a few questions.

I have a 74 Dart Swinger Slant 6, my goal is to get a 360 in the car and running, then i can do a “build” down the road when more money comes in and get into new pistons, heads, etc.

My current trans is stamped A904, will this work with the 360? I read I would then not have a need to shorten my driveshaft. With the most popular trans are the 727 and 904, is mine that same 904?
Yes. You have an A904, but yours is slant 6 specific. The slant 6, small block and big block all have different bellhousing patterns and their own separate transmissions. So you will need a small block transmission.

Next question is, my plan is to throw a cam, then obviously header, exhaust, maybe bigger carb and intake. Would my stock 7.25 rear suffice or would I need to look for a 8.75? And would my 904/stock driveshaft work with that 8.75 rear?

The 7.25 will probably live a little while, because likely what will happen is, you will obliterate the right rear tire, instead of breaking something. It's doubtful it will last a long time, so make plans. lol

Would I be able to install a floor mount B&M shifter with my 904 if I can use it? What does installing a floor mount shifter on a column shift car entail?
Of course. Just follow the deestruckshuns for whatever shifter you choose and we'll be here to help if you get stuck.

thanks in advance all!
Sho nuff.