Comp cams xe268h for 318
Or higher actual compression ratio..... Was that a later production 340, like a late '72 or a '73?
Agree with Mike seen it too many times cam duration one or two sizes too big for the application/ current build
we had that "coming up on the cam" in the XKE with the ISKY XM-3 (or XM-2 on the intake and XM-3 on the exhaust which was better
you tried to keep the rpm above the power tip in point but if you went below you were dead and if they came on on a curve you could loose it
so a rant
Comp XE268 was a great cam- state of the art in 1977 when the Late Harold Berkshire designed it- before Ultradyne and after General Kenetics
The stock 340 cam and the 340 stick shift cam have their 50 year anniversary this year (the stick lobes may be borrowed and even older)
I think these were Camcraft designs- the older gentleman there, I'm forgetting his name- did great work
But what computers were available in 1967? How many degrees between lift data points, and smooth with a file/ stone and an optical comparative system
That's the way it was with most till Harvey Crane publicized his "computer smoothing" program, and tough in cheek offered to smooth other grinders profiles.
Today you can have a CNC grinder grind from a computer file with no master getting in the way and adding a layer of error with CNC accuracy on your lift table and degrees
Rick Jones is doing this- you get to pick your grinder
So why does the 340 and 330 Magnum cam have such long (and high) closing ramps?
Warranties
exhaust valve seat recesion was appearing and the long ramp allowed the lifter to not make noise
later it became an exhaust gas dilution feature
no matter- neither are things that are needed in today's performance build- just compromises that hurt your results
no way around the dynamic compression hit or the excess overlap/ heat