Stu....I don't know if you want to take this route but...
There is a fix, or at least it worked for me on my 56.
I do not have OG handles either, and had to pick up some aftermarket ones too.
One handle worked fine. One did not.
I used a die grinder to make a shallow groove in the aftermarket handle (I personally don't like to cut up or modify ANYTHING original, I'd rather hack the aftermarket products) where the locking mechanism (door latch rod or what ever you call it, lol) contacts the door handles inner mechanism. (Put your door handle on, the door handle should be in the unlocked position... open/close, 5 or 6 times. It should leave a mark on the inside of the handle) Grind that area down a little at a time so when you put the handle back on, there is no (or little) pressure on the locking mechanism. This will allow the locking mechanism to ... let go.
I don't know if this will work for you, but to test it... before you grind, just hold your handle to the door, no screws in it. Try to lock, unlock, and use the inner door handle lock. No worky??? Then let off some pressure until you hear a \"click\" from the door latch. Now try everything...holding the handle in place. This worked beautifully for me. ;]
If you don't understand my post, let me know I'll try to explain or give you a hand. Still, I think the best bet is to find original handles! :unsure:
