Welcome, Welcome. Introduce yourself to the group and tell us a little something about yourself.
Considering the temp, tune, difference in wheels, and stall, it sounds about right.
7* sounds like alot to me. If you plan on going farther I would get some tuning software. Westers first near stock tune was great for me, I would never let him near my truck at this point.
I was told larger wheels/ tires as well as converters sap alot of power on the dyno as does heat.
Like F8L says, keep it up. Youll get there.

 

My mistake. They are accurate, just a bit lower.

 

The temp difference alone is huge. I think the rule of thumb is 1% Power loss for every 10 F increase in temp.

Dyno weather correction
http://www.wahiduddin.net/calc/calc_hp_dp.htm

And it sound like you have some serious tuning problems. 7 degrees is a lot.

What kind of tune do you have now. How much timing are you running?

What was the air/fuel Ratio?

 

2000 5.3l rated at 285 fwhp
replaced with:
2001 6.0l 325 fwhp crate motor ~3500 miles at Dyno time

 

So you have the LQ4....325 x .83 = 270 RWHP, so that means the heads, cam and stall netted you nearly 40 RWHP. Not bad, but definitely not great.

The first things that come to mind are the tune, heads, and ASP pulley. Who did your tuning? Did you log your dyno runs with software? What were the results? If the ASP in an underdrive pulley, there are known instances of them setting off knock sensors and causing KR. What do you know about the heads?

 

Welcome? Well, I haven't been on the site much lately.

I'm seriously considering getting a laptop and HPTuners, but it'll be a while. Would like to get a 4L80e and Turbo before that.

Isn't it 10*=10% power? I know there's a post here somewhere detailing the effects of weight and size for tires/rims. I can't recall the numbers, but I know it's significant.

 

Thanks for the calculation. never looked at it that way.

No loggin software was available. I'm getting the KR from the Predator while at the track.

Tell me more of isolating the ASP Underdrive knock. I really need to find some race gas. Maybe Later this week i'll make it to the 1/4 mile in Jacksonville, NC. They have gas there.

I never did get the flow rates of the heads.

 

You're operating in the dark if you're not logging your runs. You don't know what's going on inside your motor and as a result, any action you take is just guessing, really.

Don't remember where I saw the ASP pulley KR topic, here or on SilveradoSS.com. Try doing a search on both sites and see what you come up with.

I've heard mixed reviews on the PP heads. Don't know what to say about them because I don't know much about heads in general.

If you're interested in eeking out the most HP from your truck, you really need to invest in tuning software. I got a brand new D505 laptop from Dell (on sale) for $800 and HPTuners for $500. Also got a wideband but it isn't installed yet. But with HPT at least you can do logging. Maybe HPT and borrowing a friend's laptop if you're short on cash right now....

 

Tuning is a must. The tires are not helping, someone told me that my heavy cast 20s are eating up 10-15rwhp.
Dynos are not everything. I have seen a low dyno number car out run a higher number car, just last night. A T/A had a length on a higher horsepower Z28. The Z28 has a 150 shot, full exhaust, stall, and 3.73s. The T/A had full exhaust and a 125 shot. The Z28 dynoed 30rwhp and 47rwtq more.
The real story is the track times or the ***-o-meter.
Good luck.

 

You need to be able to tune that computer, how would you get a 6.0L with a turbo + a 4L80E to run without tuning. I bit the bullet back in the spring, Knew I wanted a 6.0L, and I knew I was gonna need to tune it, so I bought a new laptop and hptuners. $1800Cdn for the laptop, and around $700Cdn for HPtuners.

If 10*=10% then 308 hp x 1.45 = 446 RWHP 442 ft/lbs

if 10*= 1% then 308 x 1.045 = 321 HP 318 ft/lbs