Big Block 383 Assistance
 

Hi All,

Just want to get some advice in regards to the combo in my '73 Duster.

Took the Duster out on it's maiden drag voyage a couple of weeks ago and it ran 13.7 (@103mph) at Sydney Dragway in extreme heat. I was a bit disappointed with it as I honestly expected it to run 12.8-13.0 or so. It seems to have the MPH to go into the 12's.

Here's specs of the driveline...

* 383 Bored 30 thou - Flat Tops-Balanced Bottom End - Comp Ratio around 9.5:1 - Mopar Purple 484/484 Hydraulic Cam
* Unported 516 Heads-2.14/1.80 valves, Comp Springs, Alluminium Roller Rockers
* Eddy TM6 single plane intake and old (4479) Holley 750 D/P and 1" spacer.
* MSD Streetfire Box and standard Chrysler Elec Dizzy and MSD 2 Coil
* T/Flite 727, 3,000 stall, 4.10 gears

I ran it with M/T ET Radials (255/60/15's) and it has chassis connectors but stock springs.

Just trying to figure out where I'm going wrong here??? Really want the car to go into the 12's. Should I get a different cam and alloy heads??

Here is what i see you are short on......
10.5.1 C/R
Dual plane intake
VooDoo Soild or Roller Cam

Now with that said, I sure there is a little more in you combo due to weather and tune-up.... I would guess about 2-tenths....
Post up the time slip and the weather info if you have it.... :)

Here's one of my timeslips..

Temp Celcius - 31 degrees
Rel Humidity - 47
Absolute Baro - 30.12
No track temp

60ft - 2.109
330 - 5.91
1/8 - 8.977 (80.16 mph)
1000 - 11.60
ET - 13.79 (102.47 mph)

Yeah, I think there's a bit more in there with the weather. It was a damn hot day out there. Duster comes in at around 3400 pounds or so with full tank and me in it.

Just having a look at some of the ET calculators around it's saying that I should be running around 13.2 or so but I do want to get way into the 12's.

I would love to put another bigger cam in it but the one thing I do worry about is the piston to valve clearance as I have flat tops with no reliefs and the slugs are in the bore (not sure how much?). It's definitely not at zero deck.

I see it did not run well to the 330......
where you able to stall the convertor at all?
Or did you you just foot brake it and flash the convertor to what ever?

The pistons are probably 80 to 100 thow down in the hole.. :(

Nah, didn't stall it up. Just mashed the throttle on amber...

Did you notice what the converter flashed too?

I would say a few more outings are in store.... Even @ 31C it should run better...
Need to bend the rust off yourself.....lol :)

g' day cobber.
 

I have a 383 in my vf ute. It went a best time of 13.4 @ 104 mph with a 3.55 Borg warner LSD diff . I changed to a 3.9 ratio 8 3/4 diff & ran 13.7 @ 102 mph. But my engine was rooted. I,d sus out your timing & stall , you may want a 2800-3000 stall with the 484 Mopar cam in a 383 cid engine. Your combo should get you way down in the 13's if not mid 12's. Something's not working there & I'm thinking your not making the power/ rpms to turn your diff ratio fast enough?? I need to go back & read your post again. Who knows you've probably sorted this out by now. I assume you have decent headers & dual 2 1/2 exhaust ? I'd want bowl work & gasket matching done to the heads , manifold & headers & 10:1 compression. How was the cam timing set? Was it set up with to much advance on cam as I can't see the old tm manifold holding it back that much. Although from what I have read about them they aren't that good. A rpm air gap would be great , mine was a holley street dominator low rise single plane that made peak torque @ 2100 rpm with bigger hyd cam.

What exhaust ? Shift RPM ? Wheel spin ? for 383 w 284 cam maybe 62- 6500. Must have the converter stall when launching. I agree with Bob it needs more compression. I ran a 360 with the 284 cam modified zero deck stock flat tops

does it hook on launch? this is what Ronnie Sox told me a long time ago. all 4 corners should lift on launch, and the front go up more than the rear. and the bottom of rear shackle's should facing the rear about 20-30 degrees. else the rear will NOT lift.