You will need the V-8 frame, intermediate and motor mounts. Yes, they are three peices and are available from multiple sources. Then you will need the transmission adapter, also available. You will need a C4 yoke and your driveshaft will need to be shortened. Remember that you need an inch and a half of yoke play in the transmission to avoid punching the rear end gears out the back of the case. I did this swap years ago in a '63 Futura. I used a '79 302 with C4 from a T-Bird.
Now that you have the engine/transmission in there, you have to reroute the fuel line because the six fuel feed is on the passenger side where the V-8 feed is on the drivers side. A V-8 radiator will fit right in the opening and when I did my conversion a three row version was available. The battery might be a problem. The later '63s had a dimple in the inner fener well for clearance for the V-8 but the early models didn't so the battery will interfere with the generator. Throttle linkage will also need to massaged, again the carb is on the wrong side from the six. I actually used the stock firewall linkage by heating the arm and bending it in the opposite direction. Shifting was done by a floor shift that used a cable to activate the trans. I didn't try to use the column shifter so I cannot offer any opinions on using it.
That just about covers it. The stock suspension will work as long as you don't use it for drag racing, on the street or strip. The rear is too weak for that. I had a V-8 rear that came with my car. The front suspension is strong enough to hold the additional weight as long as you don't go into slalom racing. Good luck!