700r4 pains

[tlman]

ok guys help me! I think im using a 73 plus rear cross member it worked with the th350 ,now I am hitting the floor with top of 700 ,headers are pointing down,hmmm on an angle ,ive reworked the cross member and have it away from the floor ,but headers still point down slightly ,this truck has been apart totally ,only thing I can think of is that I have to shim cab up to raise the trans and lift headers up ,this is a complete resto ,original engine mounts but like I said ive reworked rear and still near floor and collectors on slight angle
Any ideas trans oil pan visually is lined up with frame rail ???????