From what I understand, a 518 is basically a 727 w/ OD & is found from '88-'96. The '92-'96 are lock-up units. A 500 trans is basically a 904 w/ OD. If that's the case (and I'm hoping someone corrects me if I'm wrong ), I would probably go with the later 518 for a TrailDuster for the lock-up feature. Several members made on the first page for suggestions of the kit to rig the up the OD & lock-up.
Tim
'71 Charger 383/727 '17 Challenger SXT (Wifeys car )
), I would probably go with the later 518 for a TrailDuster for the lock-up feature. 
Several members made on the first page for suggestions of the kit to rig the up the OD & lock-up. 
