Dyno pull

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Duster 383

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So me and my dad got the 383 duster on the Dyno yesterday and I was shocked by the numbers we got ...theses are the specs that "we have been told " about this motor

69 383
Ported and polished stock heads
Mild cam( durations unknown)
Edelbrock dual plane intake
850 Holley carb
Over the fender headers ...look like 1.25-1.5 primaries
727 manual valvebody 3200 stall

Now the third and final pull in 3rd resulted in 243hp@5500 rpm and 258ftlb torque @ 2800

Why are these numbers low ..I thought for sure the way this thing drives that it would easy be in the mid 300 range ...were my expectations to high ??
 
Header size is abnormally small, heck again.
Cam size unknown. Huge amount of information missing there, HUGE!
Ported heads. OK, unless you know what it flows , you might as well have stock heads.

What dual plane Edelbrock? There are a few of them. Some not worth more than an OE replacement and others worth there weight.

Rear wheel dyno numbers also reflect how effective or not the converter is, the 727 eats a bit of power and the true size with gear ratio.
 
Yeah it really sucks cause the owner gave us no help whatsoever ...now is it true that the stock heads on a 383 are the same ones on a 440 ???
 
A stock 4bbl 383 would have had around 325-335 hp as I recall from the factory.
Now give it 40 years of wear, a lousy tune-up, a slipping convertor and your rearwheel dynonumbers don't seem that out of line.

How about a pic of that "disappointment" under the hood...
 
and be as specific as you can with parts...what is in the engine....ignition system...timing...carb jetting?

And if you say you dont know...there is one of your problems...you are going to have to learn...and tune it...
 
BigBlockMopar said:
A stock 4bbl 383 would have had around 325-335 hp as I recall from the factory.
Now give it 40 years of wear, a lousy tune-up, a slipping convertor and your rearwheel dynonumbers don't seem that out of line.

How about a pic of that "disappointment" under the hood...
Click to expand...

IMG_20171116_082330_01.jpg
 
70aarcuda said:
and be as specific as you can with parts...what is in the engine....ignition system...timing...carb jetting?

And if you say you dont know...there is one of your problems...you are going to have to learn...and tune it...
Click to expand...
Yeah it's gonna take time to learn and I really....really want to learn so if that means looking and asking stupid questions to get smarter then so be it lol
 
So much missing in this post. I'm not even going to try. I'll just say sorry for your loss of power & torque. Chalk it up to buying unknown parts & try again. Good luck on your quest!
 
You're numbers are not low because you really don't know what you have there. Compression, cam, rear gear, and converter define numbers. ET is defined by the driver! 65'
 
AJ/FormS said:
Does it spin the tires all the way thru first gear with 3.55s?
Then where's the problem?lol
Click to expand...
If we have to explain, you wouldn’t understand!
:rofl:

Just pulling your chain AJ!
 
BigBlockMopar said:
A stock 4bbl 383 would have had around 325-335 hp as I recall from the factory.
Now give it 40 years of wear, a lousy tune-up, a slipping convertor and your rearwheel dynonumbers don't seem that out of line.

How about a pic of that "disappointment" under the hood...
Click to expand...
I’m under the impression that this dyno run was a rear wheel test.
 
When it was on dyno, did they record air/fuel ratio. If so, that will give idea about carb tuning and jetting. A good start on tuning is to do compression test to see if any major concerns with rings or valves. Then check and/or set timing to about 15 deg initial and 34 deg total. See how runs, then just enjoy what you have or start over and rebuild with known parts.
 
BigBlockMopar said:
A stock 4bbl 383 would have had around 325-335 hp as I recall from the factory.
Now give it 40 years of wear, a lousy tune-up, a slipping convertor and your rearwheel dynonumbers don't seem that out of line.

How about a pic of that "disappointment" under the hood...
Click to expand...
That number is at the crank, not wheels. And the HP numbers is dependent on what head it has.
 
3406pk said:
When it was on dyno, did they record air/fuel ratio. If so, that will give idea about carb tuning and jetting. A good start on tuning is to do compression test to see if any major concerns with rings or valves. Then check and/or set timing to about 15 deg initial and 34 deg total. See how runs, then just enjoy what you have or start over and rebuild with known parts.
Click to expand...
the stuck a sensor in the tail pipe ...@ idle it hovered around 10.7-11.3
@2000 rpm 11.5-12.4
The rest of the rpm range was around 12.4-13.1
 
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