AINT SKEERED

iTrader: (2)

my mix up. Didn't catch the 383 part. In this case yea it's a tame cam.

Darth_V8r

iTrader: (4)

Because shift points are about more than just peak power. They're about gear splits. If you shift at 7300, your upshift is going to hit 4800 or so in the next gear. If you do the math, you're still making more torque in first than you are on the upshift to second...at the tires. Not the engine curve, but multiply by gear ratio also. So, you ride that gear until your torque matches on the upshift. then you ride that torque curve down until your upshift torque matches again. if possible, you'll shift so your peak power is right in the middle and you maximize your power under the curve. Don't forget there's power under the curve well past peak.

That's how cars with less power outrun cars with more power. By stretching their gears with RPM

64post

iTrader: (5)

I think I see what you're saying,kind of, is there not some issue with nosing way over past your engine's most usable power and losing out? There's too many variables there like transmission gear ratios and the distance between peak torque and peak hp. If they're close then what you say is easier done, (if I understand correctly what your saying) but 7200? To get back to 4800 at the next gear? That will be 8-900 rpm past for him .

JakeFusion

iTrader: (7)

That cam is a good profile... I had it. But it's not going to spin like crazy in a 383. The IVC is too early. You're not getting 7200 out of it. You're not getting 7200 out of it in a 346.

If you had it cut as a 234/246 114+3 it'd get there. Later IVC... and more exhaust duration would carry more uptop. This is the profile I've toyed with as a streetable 383 nitrous grind with 11.5:1 CR.

Darth_V8r

iTrader: (4)

800 past peak is fine. i'll use a real-world example: My old hydraulic cam which peaked around 6500 RPM in a 346. it was a 227/235-112+3. 470 peak HP at 6500 rpm, and 417 peak torque at 4900 rpm. I revved to 7200 all the time in it just horsing around on the street. By the time it reached 7200, torque had fallen to 340. So It's down almost 80 vs peak right?

First gear ratio is 2.66, and second gear ratio is 1.78

If I take first out to 7200, the actual torque delivered through the driveshaft is 2.66 x 340 is 904.4. On the upshift, I end up in second gear at 4800 rpm, so right at peak engine torque. So I'll use 1.78 x 417 is 742.26 actual torque delivered through the driveshaft. So, if you see, even though torque has fallen off, and I landed RIGHT AT peak torque on the engine, it was STILL advantageous to ride the RPM out way past peak. In fact, if I ride it all the way out to 7500 rpm - and torque had fallen to 300, it's STILL 800 lbs of torque vs 742 on the upshift. RPM is ALWAYS advantageous, even if it "noses over"

This brings up a different point - it's about the combination of parts, not any one particular part. My experience on a 227/235-112+3, which is even smaller than either cam mentioned here with an even earlier IVC revved to 7200 fine. But EVERYTHING has to support the RPM, not just the cam profile. Jake's right, a 383 won't rev out like a 346 all things being equal. The LS7 revs out on a 211/230 with a 48 IVC, and that's an even smaller cam on an even bigger engine.