I have both subframe connecters, and the cross brace from TCP, and I AM installing them on to my 68 fb, I am having problems with getting both front and back mounting points up high enough to weld on to the subframes. Basiclly the subframes seem to be teter totering, by about 1/8 or so. ( I get the backs in place and tack welded, but then it cause the fronts to drop down, and then I can not get the front to seat well enouigh with out removing the tack welds) The car is a shell, and it being support on the natural weight/suspension points by jack stands. I want to know if any one has add a issuse like this, more so if by doing this will help or hurt some other structural thing. If place another set of jack stand on the ends of the subrames close to the torque boxes, and removed the other jacks from the weight/suspension points in an attempt to allow the weight of the car to get the sub frame to settle into place. I want to know if this could damage anything? I think it would actaully may help since the car is not sagging so to speak in the middle. (one this note the car is very straight and solid and the is little deflection in the door jams). any information would be helpfull.