Back in the seventies I had a 340 six pack 4 speed manual trans with forged pistons 292/510 purple shaft cam and heads were just home clean up of the ports and valve job at home by my father. That thing was a rev monster! After running it in I took it for a run down the road and it pulled past 6500 on the tacho before I changed in every gear. I would rev it well over 7 grand when showing off but max power was at about 6500.Yes it had Hydraulic lifters and std rocker arms.The hdro lifters were not stock but out of a drag car of the time 383 two barrel that ran low tens. Looking at them you could see where the oil hole had been welded up and moved but I did not know if the internals had been modified but you could easily get to mid seven thousand revs. No one could believe how that thing could rev with hydraulic lifters.