I for one didn't realize that you were running with adjustable rockers on the 318. What you found leads me to wonder if you adjusted the rockers properly. Sounds to me like these were adjusted of a bottomed out lifter rather than with the plunder at the top of the travel plus 1/2-1 turn with no more than 2 threads showing below the adjuster. Hopefully you didn't use 273 solid lifter push rods they will be about 1/4 inch too long.
Glad it is running.