that's the correct part number on that skinney o ring. You might try a dodge dealer, it's the same seal as the caravan.
On the finger between the gear and head thing, just remember that the valve springs on the cam are set like a mouse trap.
I use 2 small heavy duty black paper clip things on each gear to hold the T belt on the T gears while install the belt,,,makes the job easy/ less aggrevating.

dave h.
'89 Raider V6 5spd;Aisin Hubs;; Gen2 LS: frt. brakes, rear coils;U.C.arms;R.trailing arms;idler arm; rear LSD axle w.disc brakes ;2 battery system for Dog's fan; relocated ECU; custom bumpers;J.Baker receiver;Conferr roofrack; t-bar crank.