So I finally got my car dynoed, and I was pretty suprised by my power curve. I know strokers make most of their power down low, but I have NO top end. Here's how the numbers came out:

Rear-end power: Max TORQUE=366.4 Max HPOWER=250.8

My torque is all bottom end. That 366 was at just below 3,000rpm, and it dropped like a rock to about 235 at 5,500 rpm. My HP was Just over 200 at 3,000 rpm, and the 250 was at 5,500 rpm.

My cam is from Crower and is supposed to make good mid-range to high-end power. Duration at .050 is 218 and 226, lift is .462/.470, and red-line is supposed to be 6,200+.

So is that normal, or is my car running weird? I was really dissapointed with my HP, and I wish my torque wouldn't drop so far so fast. Any ideas?

 

I'm far from an expert but that cam sounds little small for the motor.

Its slightly smaller than the ever popular LT4 Hotcam which tends to peak ~5800-5900 on a 350. In a 383 a 5,500rpm peak doesnt sound too far off. But 250rwhp is still pretty weak though. How well do the heads flow?

My $.02...

 

Well, from what I've heard the heads I have are supposed to flow really well, but I'm kinda wondering. The shop that built the engine said they were Dart Sportsmen II heads, but I can't find any info anywhere on them.
When I had my valve cover off the other day the head said Iron Eagle on it, so I'm really in the dark as to what they really are.

 

Find the flowsheet, but that doesnt sound too far off from what i'd expect from a 383 with a cam that'd, IMO, be very small in a 350, much less a 383.... and those heads, if i remember correctly.. they MAY peak around 240cfm int. I honestly dont remember though, wish i could say for sure

 

This really should be posted in 3rd Gen Tech. Moving there now...

Thanks.

 

Chevy High Performance has an extensive list of heads that they have flowed. Check out their web sight to find out how your heads really flow. From what I remember, they are a little weak for a 383. If the shop that built your motor just bolted them on out of the box, there's about 25-30 hp to be had from some good port work and valve job(sounds like a good winter project).

Once you get flow numbers, the cam should be matched to the heads. Your motor should accept a cam with 230/236 cam with lift somewhere in the .500 range.

The numbers generated on the dyno are a little weak. 260hp @ 5500 rpm translates into roughly 305 at the flywheel. The problem is that the motor is out of breath!

www.geocities.com/dzperf

 

I believe it to be your cam also. Its a bit small for a 383. Your heads need to be ported too. I bet with a cam along the lines of what I have and a good port job, you would be making a little closer to 300RWHP. That translates to about 360 or so at the crank. Thats not too shabby.