Originally Posted by
rgu
Hi
Early on in FST we had a lot of stock aluminum pushrods break. Some builders switched to chrome moly pushrods but those were heavy required too much spring pressure. The CB's you got are known hold up as do the Mantons and the Smith Bros-all seem like the alloy and wall thickness are appropriate. Next question of course is the valve spring question. PM me and I'll go through the alternatives and valve seat pressure with you. You can find a list of parts quality discussions on our website. formulafirst.org
Regarding your tach:--While I'm told Willow is a very fast track, 6700 rpm seems a bit high if you were running alone. I would borrow another tach that is perceived as accurate. Just a guess on my part but 6200-6300 outside a draft might be a better expectation. I've even seen someone wire up a Garmin and read out MPH as a tach checker.