35 pickup Shock dogbone

[Jakno]

Having problems getting a full nut on my 35 pickup tapered dogbone bolt ends, on the shock arm and on the frame ends. Can just about get a half thread and then the taper closes up.

The shocks I bought used on the Barn and M Bartlett N.C. re-built them for me. Both left & right front dogbones have the same issue. The rear shocks bolted up fine.

Could I be trying to mate up different year parts ?. I bought them as 1935.

Almost ready for my first test flight after 1.5 years. Thanks for anything you could offer.