Lifter questions on 68 307

[aggiegrad]

Got tired of the blue smoke on startup of my 68 daily driver. Replaced the o-ring and umbrella valve stem seals but ran across an issue when I went to tighten the rockers up. I am new to this so I looked at the methods to adjust 1/2 turn past zero lash for Hydraulic lifters. However, only one of my lifters has any give indicating it is hydraulic. Cylinder 1 exhaust allows you to push it in 1/4 in after zero and I set it as indicated (1/2 turn past 0) and everything seemed fine. Every other pushrod felt solid and if I tried to adjust 1/2 turn it would open the valve.

I am wondering if there is any logical reason for this. I assume the PO did not install 15 mechanical lifters. Also, it does not make sense for all to go bad.

The truck is the original 307 and has been running fine. We drive it regularly the past 2 yeats and daily for the past 5 months.

I am worried to crank it back up but I dont want to remove the intake either if there is nothing to worry about.

thanks for any help.