Since the cam only turns at 1/2 the speed of the crank they would suffer much less than the rods and mains. If you need this to be dependable you need a rebuild or another engine.

I've owned a few Dodge 318's in my lifetime, and found them to be extremely tough and reliable engines, but with nearly 300k miles on it, I'd say your little 318 is about done. I'd go for either a COMPLETE rebuild or a new short block at the least.

Since you kept driving it with zero oil pressure, cam and main bearings may be the least of your problems.

Well where did the cam bearing go exactly?

i have a 98 Dodge ram 1500 318 4x4. i got it after driving 10-15 minutes the oil pressure dropped to 0 and would come back up then back down i drove it to the shop (by that time it developed a slight rod knock) and i put in a new oil pump and rod bearings. i started it back up and still 0 oil psi.Now it has very noisy lifters. i drove it home and it stalled when i got home (about 6 miles) and wouldn't crank enough to start (temp was 190). i go out in the am and it fires up. Would new main bearings fix this or would it be a waste of time? it has 267k