That's too bad the damper did not do it's job.
When I was using stock damper,my engine would only turn to 6000 RPM or so,but struggleing to get there also.
I did nothing else to my engine but install the 8" GM damper & man,what a difference! Smooth up to 6000+ RPM.
It wanted to rev much quicker also.
I later installed my Paxton supercharger blowing through 3 48 MM Weber DCOE's & it would want to go to 7500 RPM
I run a stock 8" HP GM damper. This damper totally smoothed out my engine & I turned to 7500 RPM w/it,not too wise w/a cast unit,but I did so anyways,because of no money @ the time.
I have heard good things & bad things w/fluid dampers.
My new engine will have a Vector damper.
Sounds like another test w/a good damper & Langdon headers .
MBHD
Previous quote" Any guess on how much HP loss w/the cast iron headers?
I am guessing not too much if any by this engine build,but hey, I could be wrong"
