what gives

On the left is a rocker shaft that came with adj rockers from I thought was a 273. On the right is a shaft from a 273 with solid lifters. Came out of my 66 273 charger engine. Now the reason for this post is I installed the adj rockers using the shaft on the left and I did not get enough oil flow to rockers. I have asked about this on other posts. I mean ran it 3 min and still almost dry. I can see the for sure 273 rocker shaft would oil better. What gives? I only have one shaft like the one on the right, when I got car the left head was missing. Thanks. MT:burnout: