I spoke with John (Zannetti) he's the one who talked me into getting rid of my cases and said once I get everything together give him a call and we'll set up a day that we can do it together... Balance the wheels and fit the crank... Said he wanted to balance it to 60%.

 

Doing an older lower end correctly is an art form, watching someone who knows the their game is a thing of beauty.

 

I really don't think it's lifter pump up, the culprit is valve float, loss of valve/spring control, google something like "spintron loss of valves/spring control".
Seat and over the nose(max open) pressure needs to be checked, it can vary plenty depending what type of spring, installed height and max lift.
Cam profile and inertia of the weight of the valve/spring/retainers will affect what rpm control is lost(valve bounce, float)

http://harleytechtalk.com/htt/index....562#msg1144562

I'd rather be a little not out the box heavy, than light on pressures, some parasitic loss beats broke parts.
Limiter on the Twinky is set at 6600.

 

I definitely know that spring pressure will cause valve float and will check that.. I'm pretty sure that when my stage III heads were done with BeeHives that were good to .650" lift that I wouldn't have to worry about that....The only time I ever had issues was when rpm's went over 6500 rpm (actually hit 6860 once)... As for Hydraulic lifters, No one that I know of will set their RPM reliability ranges over 6200. They're not solids, thats for sure.... those times that I did float a valve or a lifter pumped up, I never meant to over rev my motor but with the build and gear ratio's it jumps up so quick. The next think you know, POP..... Thats why I set my rev limiter to 6000 rpm.. If my tach had a shift light maybe things would've been different... Usually on a street motor there's no sense in going over 6k anyways.... Won't be long now that I start the rebuild.. Any other tips or suggestions are always welcome... Thanx Bob..