What affects power more in a camshaft....high lift or longer duration?
The duration at .050 in the first chart is just the number you get by multiplying the advertised duration by .85. Not accurate, not sure why Mopar Performance ever pushed that. The chart below (which I think I might have got off this site) I'm pretty sure has more accurate @.050 numbers:
View attachment 1716501320
I've come to realize they pushed the 850 figure and didn't use it. They used "somewhere" in between the 777 standard everybody else used and 850. Because when you do the math, none of them math out using 850. I am almost 100% certain they did that for proprietary reasons. They simply did not want people to know their camshaft formula.
To add to that, I never really cared and here's why. In the Mopar engine book, there are recipes for different ET brackets. Wanna run 13? Here's the recipe. Wanna run 10s? Here's that recipe. Guess what? Fifty plus years later, THOSE RECIPES ALL STILL WORK!
Looking at it from that perspective, who gives a FIG what the camshaft specs are? Just pick out an ET bracket recipe, build accordingly and GO RACING! No other manufacturer ever did that.
Yeah, it'd be helpful NOW, since Mopar Performance is pretty much defunct for our old stuff, to know those cam grind formulas, but we don't. I don't think Mopar ever thought about a day when MP might not exist. I wish they had.
The best thing we have now besides the Mopar stuff, if you want close to those is Racer Brown. I'm sure he still has all those grinds filed away and he will whoop you one up real quick.
How old is Jim now? Rest assured he ain't no sprAng chicken. Everybody retires sometime. I don't know if he has family in the business or not. I sure hope so.
All you young guys (Not necessarily who I replied to) can piss ***** and moan about how "archaic" and "dated" those MP cams are and how there are "much better" grinds available now. All those grinds did and still do EXACTLY what Mopar said.
Here's the kicker. Yeah, their ramps are "slower" and "not as modern" as the latest and greatest, but you know what? MY valve train with an "old archaic dated Mopar cam will last longer because it's not being beat to death by what some consider to be "better" lobes.
There's always more than one way of lookin at things.