221/227 @ .050”, 276/309 adv, .438”/.456” lift, 112 sep
Personally, I wouldn't run that 2120.
The 221/227 are good .050 numbers. But not for a stock 8.4cr long-block.
The lifts are also good , and so is the 112LSA.
But man the 276 intake duration will kill the low-speed torque.Let me rephrase that; it will
absolutely kill the low speed torque.
In at 110, the ICA will come in around 68*, and the Dcr will drop to 6.56@123psi, with an 8.4Scr engine; and your engine may not even make 8.4, so the actual Dcr could be even worse. I would stay far away from that cam. 276 less 221 =55* ramps. That is just too slow. It might require a 2600 or a 2800 TC to be driveable.And the fuel economy will be atrocious, compared to any power increase.
You need a cam with 50* ICA up to maybe 54*. A 54 * ICA on an 8.4 360, might get you a 7.2Dcr@140 psi. I wouldn't go any bigger for your intended useage.
Oh wait, that's the ICA of the stock cam! lol.
Ok here you go; That's right about the 54* ICA, but you can manipulate the other numbers to get it. For example; you can spec an LSA of 108* on a 262 cam. This,in at 103, will get you that same 54*, but the 262 is 1.5 sizes bigger than the 252stocker. The 108 LSA will concentrate the power on the peak, which with a one-gear run to 50ish mph is perfect. So then, all that remains is to get the lift up to the max that the heads will handle,and to whack the valves open as fast as the grinder dares go. Then run whatever springs the grinder tells you to, and limit the rpm to whatever he says, to keep the lifters on the lobes.And finally run a minimum lifter preload, so that if you forget to shift on time, the darn thing will still idle with the lifters all pumped up.
Now this cam will keep your bottom end as strong as it is now, allowing you to keep the factory TC (it is a 2250 right, and not the stock 1750 teener TC,right.) And you get to keep the 3.23s. Don't worry about the TC for now.
Then from about 3200 to 3600 that cam will start to announce it's presence. But it will be done early with a strong pull to the peak, and then you can stretch it out some. Get the anti pump-up lifters.
Anyway that's just one recipe,
I might chose an even tighter LSA; say a 104, and a 268* intake duration.In at 100* this will also get you a 54* ICA. This is more a 4-speed cam but again in a 1- gear run to 50ish mph, who cares about the narrow powerband! This will bring a tremendous boost at the power peak with no sogginess below the stall to 3000 zone.This cam might have overlap of 64* so now headers will really make a difference, a very powerful difference as the overlap is kindof a supercharger effect.
Yeah, I like that one.
Of course if you were to get a 2800TC, you could sacrifice a lot of lo-speed torque, and so run an even bigger cam on that same 104LSA..... decisions, decisions,decisions.
Keep in mind I have assumed a 1-gear run with 3.23s to about 50mph at about 5400rpm, with that 268*,lol.When you shift, that 904 will drop from 5400 to 3200, and that 104LSA cam is back to square one, lol; I think I can, I think I can, I think I can........
