Do I leave the current cross member in?
I believe you are talking about the cross member that the bell housing feet attach to. It will probably be in the way. De-rivet it and save it.
The front cross member will be left alone. Be sure you mock up the motor and trans with the new cross members and pads bolted to trans and motor so you can see any problems. Need to check clearance of the front cross member to the bottom motor pulley, adjust for fan, firewall, exhaust and steering clearances. Just rest the motor, trans and their cross members on the frame, hung off a cherry picker/stands and study it all for one sleep over. Carb mounting surface level. Motor has "built in" 3-4 deg down angle. This all needs to be done with the front clip off. Comes off in one 250lb piece. Hood, radiator and bumper off first, then clip, then old motor/trans. If you have done this before let me know. I don't want to tell you what you already know. If you need any more help, no problem. Lot's of guys/gals here have done it and have great advice/suggestions.
I see a year ago you were talking front end/brakes, did you do that yet?
