Got a 1967 FJ40 with an F block and 2F head and long tube headers...I recently had a shop do a head gasket replacement, prior to the head gasket going bad the valves were pretty quite..Afterwards I have valve ticking and one that tends to constantly loosen..Oil gets to the head..Im running 20w-50 oil..I reside in Houston so no extreme cold..What could be the issue with the valves post head gasket job? Do I adjust for the model of head or block? Do they require a break in period?