thunder550

iTrader: (70)

I thought these things were supposed to be torque monsters??

I have my AFR's down almost exactly now, 14.7 cruising and 13.0 under load. I'm commanding 23-24* of timing when stalling up, and I can only hit about 2400 RPM (used to get about 2800 with the Radix/6.0). I can barely scrub the tires when I brake stall and pop off the brake, and I can't even do that when I just nail it from a dead stop. It doesn't really start to take off until I get up over 3000 RPM. Any ideas?

JT-bo

Is the 408 blown or N/A?

thunder550

iTrader: (70)

N/a, 9.5:1 Cr

Hemi Killer

iTrader: (6)

That is weird. My 383 makes tons of torque in the 2000-3000rpms and spins the tires at will. You should have more than that with the 25 extra cubes.

03sierraslt

iTrader: (22)

You are used to supercharger low end torque.

Dock Rocker

I know my motor is a different animal than yours but my 383 is a beast off the line. That is where my band really pulls. You must have some other issue you should be able to fry the tires off the line

slowec

iTrader: (9)

Have someone else eye your tuning. You forgot something

trever1t

iTrader: (14)

You did the 80e swap at the same time?

Most report that the low end SUCKs on the 80e but I would still think you'd spin 'em at will.

hirdlej

iTrader: (31)

Please, take no offense but that is a gargantuan of a camshaft you have there for that 4800lb+ beast my friend. In a motor that's 408 cubic inches in that heavy; lifted truck, I would have shot for something more around the lines of a XR273HR cam with a 220/224 duration and a .530/.534 lift on a 112deg lobe separation with your lower 9.5:1 compression. Whoever recommended that cam to you should be shot. Sure, if you want all out ***** to the wall top end power and a heavy loping cam, what you have is fine. But if you want gas mileage, instant tire busting throttle response and an overall more pleasureable truck to drive, get that monstrosity of a cam out now. I am willing to bet your peak torque doesn't even come on until 4800 RPM's or so with the current camshaft you have installed. Do keep in mind, if you go to a smaller camshaft and someone says "Don't do it man, your power will die past 5200", who gives a flying flipper? Fact of the matter is, you have 408 cubes and regardless of your powercurve tapering off, you still have almost 100 more cubes than the rest of us schmucks with our 4.8's and 5.3's. You'll still vaporize us like we never existed. Design intelligently, match perfectly, do it once and be happy.

vanillagorilla

iTrader: (1)

What kind of TC do you have? Is it the same one from your 6.0/Radix setup? If so, then the reason why it stalled higher then, is that you were making more torque with the Radix. As for not breaking the tires loose, I'm guessing it could be something with the tune. I don't know what though, it seems you have all the bases covered. Even with the shitiest of tunes my 4.8 N/A could still break the tires loose. It really sounds like you activated TM or something. Which brings me to my next suggestion, and that could be the timing. Maybe it needs some more. 23-24* isn't a whole lot when dealing with a N/A engine. I doubt it's your cam being too big though. That's an oxy-moron!