Sm 420 Or 465 On 4.3l V6

Here's my 2 cents...
I put a 318 poly-sphere & NP435 in a 1965 Dodge Power Wagon that had a slant 6 & 3 speed column shift. I loved it. It was such a dramatic difference from the 6cyl, however, that anything was an upgrade. The NP435 is a dream to overhaul. No press required. It's still the easiest shifting 4 speed I've owned.

I already had a Ford T18 for my current 1971 CJ5 project, otherwise I would have used another NP435. At the time, the T18 was the shortest 4 speed option with the Novak adapter out there.
I use 1st gear frequently on the trails. I can usually skip low range for gentle trails which is nice. The T18 shifts smoothly and precisely.

I have 4:88 gears and a fresh Dauntless. Unless I come to a full stop, I only use 3rd and 4th gears for city driving. The new synchronizers works so well, that clutching is almost not necessary.

If I had to do this all over from scratch, I'd use a 4.3 with the SM465.