1954 chevy distribrutor and pushrod question

[29tons]

I bought a 47 chevy coe with a rebuilt 1954 chevy 235 serial number 0442022T54y. The man that owned spent a lot on the engine after it was rebuilt and run for a short time it had a miss. He said that a push rod bent . He said he just gave up and sold the truck. I think I found out why the push rods were bent because valves were not adjusted properly. I straightened the pushrods and got it running. I also checked the compression. 125-130 every cylinder. now I want to get new pushrods and lifters but I need to know if the ones in the motor are correct pushrod is about 11 1/4 lifter 2 5/16. The bottom of the pushrod seems to be mushroomed is that the way it should look? Next problem is that when the motor was running I noticed the distributor was not advancing. The vacume advance is good but I found an oring under it I dont think it belongs there and its stopping the distributor from advancing. I figure it was put there to stop oil from leaking out. dose any seal belong there. I will try to add pictures of these items. Thanks for any help.