FWI you can get Leaf springs from the oval track venders like Speedway Motors. They have different rates and Arch heights. also have specific for dirt or asphalt so I would guess you would want asphalt ones. you can get correct ride height with lowering blocks.

Managed to get em in. Took a fair bit of filing in the middle of the hex flats which was a pretty big PITA from under the car, and had to strip almost all the powdercoat off one bar.

Hoping to get the QR steering together and get the steering wheel centered to the potman this Sat.

Old thread but i thought id add my experience with torsion bars, particularly zero clocking. Everywhere i looked including here said they would be a drama especially in a big block car, concerning getting enough ride height. I have a Valiant with 383, AND, 2 inch dropped spindles. This had me pretty worried, i bought them off a friend before i did research 🤦🏽‍♂️
Anyway, theyre 1.07” and went in great. I wound it up a fair way initially, still have about 1/2” adjustment, and i need to drop it back down an inch and a half.without the drop stubs it would be way up in the air.