I'm working on the same project.....
I'm in the middle of a 4.3 / 700R4 swap into my '63. It's all mocked up right now, except for the headers. I used a bowtie overdrive crossmember to correctly set the position of the trans (using a Vega driveshaft). The motor mounts, oil pan, and headers are the biggest challenges so far. I bolted a pair of plates to the block at the location of the factory motor mounts, which extended forward to a pair of V8 frame-to-motor mounts. I then custom-fabbed a set of U-shaped saddles out of some cut-apart square tubing for the link between the plates and the frame-to-motor mounts.
I am coverting to a Bills II rack and pinion setup (picking up the rack this afternoon), so that I can use a factory oil pan. You will find that a 4x4 4.3 oil pan out of an S-10 blazer will clear the rear-steer setup, but is probably too deep, especially if your car sits low.
I have a set of rare aluminum "Bowtie" 4.3 heads that were originally used on Busch cup stock cars back when they ran V6's. These are angle-plug heads, which require headers (factory cast iron exhaust will not work due to the angle plugs). I have a set of 4.3 headers designed for an El Camino / Malibu that I am modifying to work with the setup.
I am using the Edelbrock carbureted intake, and a factory 4.3 HEI distributor which does not require computer control. This will be "phase 1" of my ultimate project, which I intend to convert to fuel injection at a later date.
There are a couple of 4.3 powered early Novas around. The first one I remember was done by a guy named Mark Grimes, back in the late '80's. He was a top-notch rod/pro-street builder who built an absolutely drop-dead gorgeous '62 Nova with 4.3 and auto power.
There is another one one a well known rod-shops website (I'll post the link when I get home) using a 4.3 and 5-speed manual trans. That car also uses a TCI or Heidt's front end (I forgot which), making the exhaust and oil pan issues much easier, but at a definite cost.
