Take the front secton of the '56 frame back to the radiator crossmember. That will provide the bumper mounting holes. Get 2 pieces of 2x4 steel tube 1/8" or 3/16" thick, and long enough to weld to the side of the '56 frame rails to the camaro clip . Mock it up in place with the bumper and brackets attached. Be sure you have the nose on the '56. If you have the rear steer camaro ('67-'69) this will be real easy. If you have the front steer camaro ('70-'81) you going to have to deal with the steering box possibly in your way. I did this set up on 2 trucks a '54 chevy panel with the camaro rear steer and a '49 chevy pick up with the camaro front steer. Once it's mocked up and everything looks good tack weld it to the camaro clip. Then take the nose off, take the bumper and brackets off and weld up everything. Gusset and plate as you feel necessary. Then trim off the camaro frame ends to clean it all up.