I recently acquired a 74 Plymouth Valiant with a slant 6, 3 speed on the floor and would like to upgrade to a 360. I have no clue as to what is required to swap these 2. Bell housings, clutches engine mounts and K-members, etc.
You either need a V8 K or what are called "swap" engine mounts. There are a acouple of manufacturers, I've forgotten where they ended up, as one outfit sold
You will need a bell FOR AN A body. Pickup/ van bells won't work.. Wander over to an outfit called Brewer's Performance.
The pan only fits 360, not 340 or smaller, and as mentioned you will need "car" (front sump) pan and pickup.
What are you intending to use for a transmission, AKA is the slant a stick, and are you thinking of that? Four speeds, EG, are A body specific, AKA short tail shaft.