1999 Ford F-350 Super Duty SRW SUPER DUTY

1999 F350 7.3L Needs glow plugs and wiring harness but still fires right up when plugged in during cold weather and zero problems in the warm weather. Has an oil leak around the valve cover but who doesn't at this age? It's a 27 year old truck made it work. Both batteries are newer. No problems with the transmission.