Could it not be getting enough fuel? Anthony told me Jerry tested a 181 and the C3 together and it was running out of fuel when they tried to tune it. He is sending Jerry larger injectors. That could be the issue and it's pulling timing upstairs. Your 60's are awesome!! Just looks like it has nothing on the upper RPM range. I think this this combo is going to work out great once you figure out the minor issues. I would say get the new tune Jerry has, possible larger injectors, meth, more cooling mods.....Don't give up!!