I have a big block MOPAR 493 engine used for bracket racing. The runs are mostly 1/8th mile now days and I'm shifting at 6400 rpm. How many runs before the Comp Cams 829-16 roller lifters need to be rebuilt? Has anyone gotten their lifters rebuilt by Comp recently? If not is there a shop where you can send them to for rebuilding? Thanks in advance for your input. MJ