Piston/Valve Clearance

[Aubrey N Bruneau]

Robert... these fellows CERTAINLY know more than I do here, so I'm just put'n this out there, as an example of where it can be.... if you're an idiot.
I run a 108 lobe-sep cam, installed 4 degrees retarded. There was just too much gained from this confifuration, for me to turn my back on it.
However... the idiot part
I have about .065" clearance on the intake... and, uh.... .038" on the exhaust
! !
My exhaust lobe is much "calmer" than the intake lobe, so my control problem still emminates on the intake side, which has required some pretty outrageous spring pressures in order to rectify.
I don't use a "chip" in my burnout, and refuse to let the engine go past about 5500-6000 during it.
I have yet to connect my two step, to properly control my launch RPM, so I'm letting out the clutch as the engine accelerates throught the 5000-6000 range.
I shift at 7000-7100, go through traps at 7200... IMMEDIATELY drop into neatral and let engine idle.
Maybe it's a combination of my "old style" techniques, that's letting this ridiculous exhaust piston/valve clearance survive ?

[Adger Smith]

Aubrey,
I can understand the reasons for yours working that way. The ex valve is small, relatively in length and size to the hulk of an intake. Longer stem bigger thicker head on that intake. I would say weight has become your enemy. What about the pusrods and pushrod angles? They are way different in the '09, aren't they?

[Aubrey N Bruneau]

Basically the same angles as a small block, Adger. My pushrod is a custom made heavy-wall Manton. Yes, they helped too. Rockers are BBC 1.7.
Intake and exhaust valves are same length, but you're absolutely right... those intakes are heavy !
Then again, if you saw the intake lobe on my cam, you'd wonder how it can run !
doh !
It really IS that crazy.
Looks like I finally do have it under control though. Didn't get out racing this year ( just closing the deal on our house, so after what we went through the last couple years, this has still been a good one ), but I DID get the valve train under control. Went out, took a few gears. My new tattle tale-tach "blew the wistle" on me, with a couple 7300+ RPM shifts
HEE HEE !