Have you driven it with the 284/474cam Yet?
That cam likes big number rear gears in addition to more than the 2500 stall. A bigger cam,(with no other changes), with a later closing intake will give up cylinder pressure, and lose kick below the torque peak, and the lower the rpm,the less kick..... and not gain it back until about 200 rpm later with about each 7 degree bigger cam.
You got the makings of a dynomite combo there, with around 10.8 to 11.2 Scr depending on total chamber volume,so you do have room for a short-ramp, fast rate of lift, cam like a Voodoo, or a solid-lifter cam.
That 284 is a good cam, but the acceleration ramps are really really long. Works great once wound up, but around town she kills cylinder pressure.......
With the aluminum heads you can run pressures of 180 psi or more.... which makes a dynomite streeter. Sometimes less is more. A smaller cam as described above will make more pressure and trapping will begin earlier, just what you need to run that 2500 and say 3.73 gears.
But if you go too small on the cam, you will have a preponderance of low rpm power, and can't even open the secondaries without spinning the tires. The 650 carb would work with that as well, whereas it's already too small to get the most out of that 284cam.
Have you figured out the deck-volume yet?
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I have a 230/237/110 cam in my 10.95 Scr 367, and really, it's too big. I mean it's fun and all to spin the tires to past the speed limit, once up on the cam. But man it sucks gas. and like I said; I could disconnect the secondaries and probably still spin to 50 or more mph, With 295s and 3.55s and a Commando 4-speed.
I had the next smaller cam; a 223/230/110 cam previously that made enough power, and got fantastic fuel mileage. I liked that cam better; it made power right from idle. I even ran smaller rear gears down to 2.76s with it.
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Where do you want the power to be?
I like my power to be "stout" at ~32mph, and if you gear your car right, the smaller the cam the more effective compression you can make down there. The problem I see is that the TF trans has a crappy low gear ratio of 2.45. So to get power at 32mph with that, at say 3800 requires 3.73s which for a streeter is getting up there already. I mean the cruise rpm with 3.73s is 65=3000 at zero-slip.
So now, if you build your engine to make peak torque at that 3800, then you will get a power peak about 1500 rpm later or 5300, and that points to a 268 cam
But in the same scenario, with 3.55s the torque peak needs to be about 200 rpm lower so 3600, and the power peak might also be 200rpm lower,at 5100, pointing to the the next smaller cam.
Yeah yur losing power at 5100 but with 3.55s, that is 45mph. Where do you want the power to be?
But there's something else to think about, namely stall.
See in these above examples, stall won't be a big deal because we're already at 3600 or more at 32 mph.
But now at zero mph, that's a whole nuther story. Say your engine makes 200ftlbs at 2500rpm WOT. The trans will multiply that by 2.45 and the rear end by say 3.55s. and say the TC will multiply that by 1.8 at zero mph, diminishing yo 1.05 as the car begins to move.
Ok so that looks like 200x2.45x3.55x1.8=3131into the rear axles which is plenty to start the tires spinning. But a car length or two later, the number has diminished to;200x2.45x3.55x1.05=1826 and the spinning has stopped.
So maybe you are OK with that.
But if not, then one or more of those numbers is gonna need to be increased.
We can't do anything about the 2.45 low gear
We have chosen the 3.55s for max hiway rpm of 65mph=2870@zero-slip
So that just leaves the torque.
So say you had a typical cam that torque-peaked at 3500, and so you selected a 3200TC. So now, say your engine makes 340 ftlbs. So you launch at 340x2.45x3.55x1.8=5322@WOT annihilating the tires. And again, this diminishes to 3100 now, still plenty of torque to keep the tires spinning. 340 ftlbs at 3200 is 207hp, so from this point on, your hp is gonna keep on increasing until you get to around 5000 depending on which cam you exactly installed. So now the 3200 has the bottom-end more than taken care of, even with the 3.55s.
But what happens when you hit Second gear?
Ok so with a 727 you have to stretch first gear out some, cuz the 1-2 split is pretty big. So stretch it to 6000, and on the shift, the Rs drop to 59.18% or 3550 rpm and now your engine is sitting right on the torque peak of 340 and into the axles you will get 340x1.45x3.55x1.05=1837 ftlbs and all you get is a chirp. So that's disappointing right?
So now your next option is more rear gear, And I'll guess it will take 4.30s so that will look like 340x1.45x4.30x1.05=2226, Hyup that oughtta do it. So now your engine is at 227 hp, and climbing rapidly to peak-power at or near 5000rpm. So the tires are gonna keep on spinning......... and 5000 in second gear with 4.30s will get you about 63mph; badaboom.
Now, if you install a bigger cam with no other changes; firstly that 200ftlbs at 2500WOT is gonna shrink, so forget spinning the tires very far with a 2500TC. By 3200 the torque is getting up again. Now whereas it was 340 with the smaller cam, maybe now it's only 320. So to maintain the launch performance, you might select a 3500TC and get back your 340 ftlbs.
Of course with 4.30s now 65=3470rpm @zero-slip..
So again; where do you want the power to be? It's all about the compromises. If you have 2.76 gears, and are not willing to change them, then yur kindof fubared.
All the torque numbers are estimates only, and your results WILL vary. They are for illustrative purposes only.
