Quote:
Originally Posted by Dave Noll
... that 272 # threw me.
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Yeah, numbers like that were unheard of(at least by me) back in the old days, for hyd flat tappet cams.
I assume that now, you can call the cam grinders that do Stocker cams, with your max lift number, and they can tell you how much duration they can grind without exceeding that lift. And they can probably tell you exactly how much spring pressure will be required to keep the lifters on the lobes, at any given rpm. They probably have computer programs that will figure all this and show you a diagram of the lobe with all the info printed out for you.
Then it's up to you to figure out how much duration will make your combo run the quickest. These cams are probably not cheap. So you wouldn't want to have to try a bunch of 'em to get the right one.
Some like to keep their cam specs secret. Others don't mind telling. Scott Burton gave the specs of the cam, lifters and springs he was running at the time this HPP article was written. His exhaust duration was also 272, but his max lift is .538. So this is a very healthy cam. The article said he has run a 10.17 in B/SA.
"...Manley Drag Race Triple valvesprings measuring 270-lb/in on the seat and 470-lb/in open.
The valvetrain is actuated by a Bullet hydraulic flat-tappet cam (268/272-degrees duration at 0.050, 110- degree LSA), which Burton advanced 2 degrees. He uses Shubeck ceramic puck lifters on the cam. Lift is 0.538/0.538 per NHRA rules..."
Don't think they make those lifters any more. And he is probably using a different grind cam by now.
Hey, I'm not trying to hijack the thread. If ya'll think this is out of order, let me know and I'll delete it.