Who's using a 16:1 manual steering box?

I have a tight factory 16:1 in my 68 small block with 215-60x15 front tires. It's great when I'm driving but it's pretty hard when parking. Like pulling in at a car cruise and backing into a space. People obviously can tell when watching. Ugh! I don't think it would be good on a tight autocross course.

On the other extreme is the 24:1 in my 64 /6 Valiant with 185-70x14 front tires. No effort at all but it is too slow!

I'd be surprised if you have 20:1 manual in your 64 Dart. Not available in that year. Direct Connection offered a 20:1 worm and gear over the counter but it had to be swapped in. Something tells me it was in the standard Chrysler parts catalog and they just repackaged it as a high performance part with a "P" prefix. I read somewhere that the NASCAR racers requested it.

Having said all that, I think you should make the switch especially in a lightweight early Dart.