Where are you guys seeing the power dropping past 5K? It's over 375rwhp from 5700-6500....

 

Exactly! For an 847 with ported heads it should be making power past that.

 

Sorry I was looking at the torque curve, but even so it shouldn't drop off that fast. My car breaks loose at the top of my gears, the torque drops way too fast, there has to be something going on in there, but like I said we will see, I will try to have my car dynoed next week.

 

Yes, that cam on stock cubes shouldn't ever really have a power drop off, you should be able to pull the car up to at least 6800 without a drop off of power.

 

That's what happenv up top, the torque always falls off up top....

 

Except for a slight dip just past 4000 rpm your graph seems to look pretty good. The only thing that throws me off is your fuel/air is not shown on the graph so it's impossible to tell how dead on your tune is. One thing you do look for is the smoothing factor and how the peaks/dips look. In your case....pretty good. See really nothing that stands out and 382 rwhp with usable power to 6900 rpm really ain’t all that bad.

Remember, its average power within intended rpm range, not peak power that tells the real story.

Hate to bring this up but ARE was not the most ethical shop in the world. (Gross understatement) I bought a whole 383 engine from ARE (long story) and it was a real piece of junk. Finally tore it apart and took the heads to Lloyd Elliott. The flow sheets showed pretty close to what you post but when flowed on Lloyds bench, the exhaust was down 30 cfm pretty much across the board and the intake down as much as 20 cfm in places. The exhaust only flowed 160 cfm @ .600 and the intake 225 @ .400 which is real weak for ported heads. Think they sent out the same flow sheet with every set of heads.

I strongly suspect this is the issue as your dyno sheet except for not showing anything about your tune looks pretty good. Because of the powerband your car is faster than the peak would indicate. Save your pennies for a new set of heads but you've got a good running car.

 

sorry it took so long to get back to ou guys. the heads do have larger valves, the flow sheets they came with acutally look pretty good. the guy that had these heads before me put down 47xwhp with a similar cam on a 383 motor, so the heads are rpetty good.

my a/f maps are underneath

 

http://i5.photobucket.com/albums/y18...ger/a_fmap.jpg

here is the link to my a/f maps

oh, i went with the 1.52 rockers because i have some weird beleif about having the cam make the lift. i know that probably makes no sense though

 

Yes but it shouldn't be that drastic, my car stock didn't fall off like that.

 

Humm..... Something isn't quite right here.

Are the flow sheets from ARE or did you have a shop independently flow the heads?? No one makes 470 rwhp from 270 cfm flowing LT1 heads if you get the gist. Plus you say larger valves. What are "larger valves?" People now are putting 2.05 valves into LT1 heads and getting impressive flow numbers. In talking to Lloyd Elliott yesterday, he said he's seen 300 cfm from some of his current LT1 heads. Lloyd tells the truth, I occasional stop by his shop and he shows me what his bench says.

Seen 470 rwhp dyno sheets all right from that type of combo, but they were also spraying NO2 into the air cleaner when they made the run. Ronald Tigg made 440 some hp with the same cam a few years ago and that was way ahead of anyone else with 383's. If you do a little research the flow numbers on his heads at that time are on a few websites. Most stroker LTx motors have a hard time making more than 430-440 rwhp and that's no lie. Those that do have heads flowing a whole lot more.

In another 385 combination I made 445 rwhp with basically the same cam, heads that did flow 270 cfm with all the tricks in the world and people called BS on that. Took probably 200 dyno pulls to get the car 100% and make that number so I'd be a little skeptical.

Your fuel air is OK but whomever tuned your car didn't take the time to dot the l's and cross the T's as the line is normally a little flatter. It just plain tells me your not getting enough air through the engine for some reason as there are no other obvious problems.

Like I say.....been ARE'd before and my butt is still sore. Been there, done that and declined on the tee-shirt.

 

the intake valve is 2.00 and the exhaust is 1.56. the heads were ported in march 2001. the heads i purchased used. he had his engine dynoed at an independant shop where his 383 made 47xrwhp with these heads and a cam of similar size (except i think it was an xe grind on 111lsa).

i am wondering if my throttlebody is restricting me as well. it is only 52mm. i tried to find the guy's dyno sheet that i bought them from but i was not able too. i am really kind of wondering if clutch coiuld have slipped. it really was shot to being with (stock clutch with 46k miles on it, lots of drag passes, and the motor never had less than 330whp for the last 25k miles). after i pulled off the dyno and was driving to my trailer that thing did not want to grab at all. even today i moved the car around and the clutch catching wasn't really happening that much, lol.

 

Your 52mm tb is OK and not an issue, but I'd dyno again and pull the air intake off just in front of the MAF to make sure your air intake is not a restriction. Seen that before. From the dyno sheet it doesn't appear to me like your clutch was slipping. If you need another clutch, I have a spare billet flywheel and disk I can let ya have reasonable.

Seriously 382 rwhp SAE isn't all that bad from a stock block and not something to be ashamed of. Your powerband is pretty good and the car faster than the peak number would indicate. I'd expect a little more, closer into the 390'ish range and if everything was perfect; even a tad over 400. I wouldn't sweat bricks on the results at all. Could be even someone put a stock thickness head gaskets on and your not getting as much compression as the cam needs.

You’ve got to do a lot of tricks like ultra thin head gaskets, electric pumps and welded/ported intake to make much more than 400 rwhp from a stock block and ported 2001 era Lt1 heads. Seen it done, but not w/o a lot of effort by someone who had been there before. The heads now are light years better than what was done in 2001 and look for yourself how many people aren’t making 400 rwhp on this list so no real shame at all. Every car can be improved!!

I would however sweat bricks regarding the person whom said they made 470 rwhp from 270 cfm heads. Something isn’t right. Hell, Lloyd Elliott only made 432 rwhp yesterday in his 383 (automatic) and I’m telling ya……seen a bunch of cars dyno and most stroker motors are very hard pressed to make more than 430-440 rwhp regardless of what you hear on the internet. Saw Jordan Musser make 472 rwhp with ported AFR 210 heads and a 245/high 240ish solid roller cam in a 402 ci block. Monoblade, tuning and a very bright person doing it, etc. No way on the 470 rwhp 383 in a below average LT1 headed car, someone's talking smack as there’s some trick or deception somewhere

My heads flow an honest 300 cfm+ and all I'm making is in the 480 rwhp range with a 398ci motor that includes every trick in the book including thermo and friction coatings. This is using a hydraulic cam on real 93 octane gas, no icing or removing belts and I do shift the bugger @ 7200 rpm..

Usually if it doesn’t look or sound right……it isn’t.

 

ok. yeah, arizona has the crappy 91 oxyengated crap this car runs off of right now. i would like to find better gas, though, i don't run the car on the street. ok, i'll pull the intake off next time i go.

when put the heads on i used stock thickness heads gasket because i had to get the heads milled 7 thousandths (i got a good deal on the heads for various reasons) and i wasn't sure if the previous owner of the heads ever had them milled. i didn't want to raise my compression too much with the gas here. i'll just have to keep working on it. i appreciate the offer greatly for the clutch and flywheel, but i am swapping in the turbo 400 very shortly. my m6 doens't like shifting in third gear under wide open throttle (it acually never gets there) so i want to pull it before its all the way broken so that i can use it in another car sometime soon.

 

I think you answered your own question when you said the clutch was slipping. Throw a Mcleod single disc or a spec stave IV in there and see what happens.

 

There is a guy on AI's website with a 355 SR using LT1 castings and intake pushing 480rwhp. Id say his clutch is toasted.