lowering a 1967 Plymouth Belvedere

If you don’t change the torsion bars, don’t lower it. You’ll end up riding on the bumpstops and the ride and handling will be terrible if you lower the car 2” and leave the stock suspension components in place.

If you want to lower the car a full 2”, you’ll need torsion bars in the 1.06-1.12” diameter range. You’ll need to remove the stock lower bump stops as well and replace them with 3/8” thick polyurethane button head bump stops. That will give you enough suspension travel and clearance to lower 2” without bottoming the suspension constantly. You’ll want Bilstein RCD’s or Hotchkis shocks to go with those torsion bars for a decent ride quality. And you’ll need an alignment afterwards.

Your other option is 2” drop spindles, but they cost $500 which is double what the torsion bars will cost. And they’ll leave you with a higher roll center and more bump steer than if you go with larger torsion bars and lower with the torsion bar adjusters. And you’ll still need an alignment and a completely new disk brake set up, because all the drop spindles use 73+ wheel bearings and disk brakes so the original brakes aren’t an option with the drop spindles.

Depending on your tire height, you’ll also need to check to make sure your tires won’t hit the inner fenders with full suspension compression. 2” is a big drop, no matter how you do it if you intend to do it right it’s going to cost a bunch in parts to make it work.