It wouldn't hurt to reground the motor, & battery to the body, to the firewall, & to the frame. I'm a firm believer in that you can never have to many good grounds on an old truck. It will help it turn over quicker, & could possibly help with your dimming issue. Just be sure to get a good metal to metal connection when hooking things up.
1957 willys wagon----shhhh, you can hear it rusting....
1969 POWER WAGON-318, 36" tires, 60 rear w/ lock, D40 front, 4 spd manual trans., 4.10 gears
1976 CJ 7, 360, auto w/ quadratrac
1978 cj-5-mated to a 94 wrangler in a strange experimen
1979 cj7, best $5000 jeep that $13,000 can buy
2006 POWER WAGON-'nuff said.'