Mopar Performance Purple Mechanical Camshaft - P4120653AE Cam Card

oh you guys are too funny!, lol.

Ok here it comes;
Lets start with keeping the 60* Ica, and see what happens for three cams of 106/110/and 114. And keep in mind that these are NOT the only combinations. I chose a split of 8* so that I could put the cam in at whatever it took to still get the Ica of 60*.. And, I am working with hydraulic FLAT TAPPET cams, which is what I am most familiar with.
EDIT: Ica is Intake closing angle; the point ,in crank degrees after bottom dead center, when the intake valve is at the advertised point of minimum lift (which is seldomly actually closed and sealed, but at some arbitrarily number chosen by the manufacturer, like .006tappet rise for a hydro.) The engine, especially at low-rpm, cannot begin to build pressure until that intake is closed.

>for the 106LSA cam, the events are;
268/120/116/276/66; and in at 106 the Effective overlap is 56*,
>For the 110LSA cam, the events are;
262/120/114/270/46; and in at 109, the Effective overlap is 44*
>For the 114Lsa cam, the events are;
258/120/110/264/44; and in at 111, the Effective overlap is 32*

>Since the Ica is the same for all three, and therefore the compression degrees are the same; then, in a given engine, the CCP will also be the same in each.
>Now, follow the progression in intake durations, the numbers in blue. Notice how the cam got progressively smaller , while the compression in black remained at 120*. To make this work, I stole/traded whatever degrees I needed from the overlap, so take a gander at those; in red.
> Notice the 268 cam has 116* of power extraction; which is a lot. You could easily trade that down to 110, to compression,like the 258 has, which would then be 124*. The CCP would pick up about 6psi, but your effective overlap would shrink, killing some power at peak. About what you get at the bottom in ftlbs is what you might lose at the top. For a streeter, the torque at the bottom is usually more valuable than at the top. But don't confuse torque and power. 6 ftlbs at 2800rpm is 3.20hp, and 6 ftlbs at 5000 is 5.72hp. So keep that in your head.
Ok so that's how that works.
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Now lets address what @rumblefish360 rightly said; namely math versus realworld.
As 512Stroker already found out, that hot XR272 was not what he expected it to be and was in the real-world, doggie down low. And we probably traced that to the long acceleration ramps from .006tappet rise to valves actually closed and not leaking.
EVERY hydraulic lifter cam has this gray area. No exceptions.
Some cams have an advertised tappet-rise rating at .006, some at .008, others at .001 So, if you don't know what you bought, it's a crapshoot, what the very low rpm will be like.
>The usual way around this for an automatic-equipped car is to just get past that soft area with a higher stall TC, which lets your engine spool up to where the power is.
>Another way around this, the way I took, is to install very high compression alloy heads, which pulls up the CCP, and so the hi-stall can be a lot less. But this comes with a caveat; Your CCP can be 175psi and more, and, as a streeter, it will probably run just fine on 87E10, full-time. The reason is because, detonation is caused by heat, and the alloy heads are really good at getting rid of it....... most of the time. See, as a streeter, you are seldom on the gas for more than a couple to a few seconds atta time because of a thing called the speed-limit. But at the track, in 95*Plus air-temp heat, your engine might spend 12 to 14 seconds or more, at WOT, doing everything it knows to do, making massive quantities of heat. So now, at 175psi CCP, maybe 87E10 is no longer adequate .... for full PowerTiming, to stay out of detonation.. No big deal, just install better gas for track-days. (For reference; My 367LA combo went 93 in the Eighth at 3467 pounds on 87E10 with 34* of PowerTiming ....... at 177/180psi. Your results may vary.)
But if you have a manual trans (like I do), you cannot afford to have that soft bottom end; because, you are almost always in that stinking soft zone. Riding the clutch is NOT acceptable.
So getting back to the ramps.
For you, OP, committed to iron heads at 9.61 Scr; IMO; you cannot afford to run a long-ramp Hydraulic roller cam. IMO, you have been forced into running a SOLID roller, in the which you can control with lash, exactly when the intake valve closes. Were I in your position, I would not hesitate to make the switch. As far as I can tell, your only other option, to use the XR274, is more Scr to get the CCP up, but that is a limited endeavor, because of what pressure pumpgas will support with those heads. They say, and I have no experience to comment, that iron open-chamber heads, depending on the quench, are limited to 160psi, using pumpgas; maaaaybe 165 with reverse domed pistons to get the Q to under ~.045.