I had the same question for my 65 cuda 340. It kept loosening up. I put the girdle on last summer, havent had a problem since. You will need to drill through the rear yoke with the supplied bolts, pretty good setup.
I haven't had any problem with them loosening up. I'm just worried they won't take the torque once I put sticky tires on it. Back when I was a kid I ripped one apart and now I'm leary anytime I get a car with the stock straps and alot of power.
Do you remember what girdle you bought? That's my hold up. I can't find one with the exact right dimensions. If I can't find the exact right one I found one real close and I'm going to order it and see if me and a buddy of mine that has a lathe can open it up a little.
