73 CJ5 4.0 head on a 258, HEI, Holley Projection w/ 4.56, Detroit lockers Narrowed D44 front and full float D44 rear T14 w/ D20 4 wheel discs, 38.5 Boggers
Biggest difference is the front fenders and hood. They are shorter. Use your 74s.
The body mounts are different, but should be able to make the mounts work. The 70 had a different brake setup where the master cylinder mounts to the frame under the floor. You can use your old hanging pedal bracket and master cylinder.