Slicks to Leaf Spring Space?

Well the only reason I´m start testing the narrower rim, is be cause this was how the SS/B cars ran back in 1968.
Possibly was the slicks more stable back than, but not much... If it ain´t gonna work, I add an inch at a time. But the fact still is, the Landy Dart pictured in post #4 was running 125 mph on 6" rims 10,5" slicks just over 10 psi. I will start with this combo, and work my way up, an inch at a time, till the ride is "safe".
Thank you for your input.