First Time Drag racing

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moparmike98

moparmike98

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nekoosa wisconsin
Last weekend I finally took my Duster drag racing at a local muscle car day. Even though the car had many issues it was a blast.
It is a 72 Duster, 360/380 magnum(Bigs 750, M1, chrome box, msd coil, TTI headers w/18" ext), 4 speed, 3.91 8.75 w/spool and adj. snubber, 002/003 springs, CE 3-way shocks all around, 295/55/15 Mickey Thompson ET Street SS.
First, some of the problems. There was a pretty solid bog off the line, launching anywhere from 3500-5k. Also found that it didn't want to shift at high rpms(like hitting a wall). Syncros? Additionally at about 4500 plus it started to pop and kinda fall on its face sometimes. Lack of fuel? We messed with the timing some and that didn't change much. Also noticed the fuel filter never really fills above half.
Best stats of the day
60'- 1.970 330-5.691 1/8- 8.814 @ 80.6 1000 11.421 1/4 13.636 @ 102.02

Planning on switching to 3/8 fuel line and a Carter strip super w/ Holley reg, MSD 6al, MSD pro billet distributor.
What do you guys think is left in her and what I should do?
Screenshot_20190923-095812_Video Player.jpg
 
@moparmike98

The 360/380 doesn’t rpm very well. It makes peak at or around 5/5.5 K. And that’s it!

Your car is heavy. It’s holding you back.
Work on your suspension and eye ball tire pressure.
Tune that carb! Fix that big, it’s costing you A LOT!


The 3/8 fuel line & hi volume pump is an excellent idea.
The MSD won’t help, the Chrome box is excellent. Recurved your current distributor.
 
Get a bigger squirter nozzle, get more accelerator pump, that should stop the bog off the line. Check your timing and bump it up a few degrees. Now starts all the fun, Tuning tuning tuning then you get to low 13's ! Then you break into the 12's YeeHa
 
I think the peak power is 5900 and I'll definitely be digging into the carb. Thanks for the advice on the ignition, save some bucks there. I am unsure on what clutch is in it because it was in there when I bought the car 5 years ago. What do people normally go with to fix the shifting if it turns out to be that? Also do I need to run the 3/8 fuel tank sender or will the stock one work for now?
 
Stock is fine. Upgrading would be better. Your not making enough power for the fuel line to be a bad restriction.
There is no strip advantage on the MSD. Around town, down the Hwy some, yea, it’s good.

Do you know what your distributors curve is?
What is the initial, mechanical and vacuum set at?
This is primarily a street car right?

Even though the clutch is a simple device, it is also a cranky one that must be set up dead on right from the start and the type/style is another consideration. Same with the shifter & rod adjustments. A simple device that gets cranky quick.

Hays and McLeaod have good clutch offerings.
 
I ran a Hays Borg & Beck with a racing disc with no marcel. It was a great clutch. Hays has a great rebuild program also, well worth the money.

also a billet flywheel that I cut about 3/8" off the inertia ring on the back.
 
Last edited:
moparmike98 said:
I think the peak power is 5900 and I'll definitely be digging into the carb. Thanks for the advice on the ignition, save some bucks there. I am unsure on what clutch is in it because it was in there when I bought the car 5 years ago. What do people normally go with to fix the shifting if it turns out to be that? Also do I need to run the 3/8 fuel tank sender or will the stock one work for now?
Click to expand...



The biggest thing that makes shifting hard is disc weight. I run a heavy sintered iron disc. Anything above 5500 and I can't shift it.


There is only two fixes I know of. Use a lighter disc.

Or you can slick shift the gear box.

I just thought of the third. You can face plate it. I can slick shift a box for gaskets and grinding stones. Face plating isn't cheap.
 
I could shift my cuda at 7000 with no problem, I played with different fluids for a while and found that ATF made it shift really easy but it would grind at high speeds, then I put in 1qt ATF and 1qt B&M Trick Shift and it never ground a gear again.
 
brian6pac said:
I could shift my cuda at 7000 with no problem, I played with different fluids for a while and found that ATF made it shift really easy but it would grind at high speeds, then I put in 1qt ATF and 1qt B&M Trick Shift and it never ground a gear again.
Click to expand...
Interesting.....
 
yellow rose said:
The biggest thing that makes shifting hard is disc weight. I run a heavy sintered iron disc. Anything above 5500 and I can't shift it.


There is only two fixes I know of. Use a lighter disc.

Or you can slick shift the gear box.

I just thought of the third. You can face plate it. I can slick shift a box for gaskets and grinding stones. Face plating isn't cheap.
Click to expand...

There's a fourth. Run an automatic.
 
brian6pac said:
I could shift my cuda at 7000 with no problem, I played with different fluids for a while and found that ATF made it shift really easy but it would grind at high speeds, then I put in 1qt ATF and 1qt B&M Trick Shift and it never ground a gear again.
Click to expand...


Is that Hays disc a rag disc? If so, that's pretty light for what it is.

I think (going from my hard worn memory) that disc weighs less than half of what my disc weighs.

I have weighed a CenterForce disc and I think it was in between the two. But that was a long time ago.

The reason disc weight is such a big deal is because of how fine the clutching teeth on the gear and synchro are. IIRC (see above about my memory) there are 36 clutching teeth on a Chrysler gear and synchro. Some of the newer transmissions have more. They really suck.

Then you have to add in the time factor. For the synchro to grab the gear and get the gear to slow down to allow the slider to engage the gear, it takes time for the disc to get to equilibrium with the next gear you are shifting to. The finer the clutching teeth, and the heavier the disc, and the heavier the disc, the longer time it takes for all that to come together.

That's why slick shifting (removing every other clutching tooth) or pro shifting (removing every two teeth) makes shifting much easier.

Then you have the Liberty rings and face plating. You can leave the synchros in if you don't use the Liberty rings or face plating.
 
moparmike98 said:
Last weekend I finally took my Duster drag racing at a local muscle car day. Even though the car had many issues it was a blast.
It is a 72 Duster, 360/380 magnum(Bigs 750, M1, chrome box, msd coil, TTI headers w/18" ext), 4 speed, 3.91 8.75 w/spool and adj. snubber, 002/003 springs, CE 3-way shocks all around, 295/55/15 Mickey Thompson ET Street SS.
First, some of the problems. There was a pretty solid bog off the line, launching anywhere from 3500-5k. Also found that it didn't want to shift at high rpms(like hitting a wall). Syncros? Additionally at about 4500 plus it started to pop and kinda fall on its face sometimes. Lack of fuel? We messed with the timing some and that didn't change much. Also noticed the fuel filter never really fills above half.
Best stats of the day
60'- 1.970 330-5.691 1/8- 8.814 @ 80.6 1000 11.421 1/4 13.636 @ 102.02

Planning on switching to 3/8 fuel line and a Carter strip super w/ Holley reg, MSD 6al, MSD pro billet distributor.
What do you guys think is left in her and what I should do?
View attachment 1715399909
Click to expand...
Lots left in her. I think mid to low 12's. You've identified many of your issues, so you'll see the ET drop fast as you get them resolved
 
yellow rose said:
Is that Hays disc a rag disc? If so, that's pretty light for what it is.

I think (going from my hard worn memory) that disc weighs less than half of what my disc weighs.

I have weighed a CenterForce disc and I think it was in between the two. But that was a long time ago.

The reason disc weight is such a big deal is because of how fine the clutching teeth on the gear and synchro are. IIRC (see above about my memory) there are 36 clutching teeth on a Chrysler gear and synchro. Some of the newer transmissions have more. They really suck.

Then you have to add in the time factor. For the synchro to grab the gear and get the gear to slow down to allow the slider to engage the gear, it takes time for the disc to get to equilibrium with the next gear you are shifting to. The finer the clutching teeth, and the heavier the disc, and the heavier the disc, the longer time it takes for all that to come together.

That's why slick shifting (removing every other clutching tooth) or pro shifting (removing every two teeth) makes shifting much easier.

Then you have the Liberty rings and face plating. You can leave the synchros in if you don't use the Liberty rings or face plating.
Click to expand...


I had a couple of those trans but it seemed I wasn't racing when I had them and they got sold. A-body hemi trans with every other tooth missing and the slider had every other tooth ground out, no synchro's. A guy I worked with gave it to me when he found out I was a mopar guy. I had it for years planning on using it then a guy building a 68 Hemi Dart talked me out of it. The disc was a custom made disc that was not offered and I had to talk the guy into making it. No marcel made it so I only had to push the clutch 1 or 2" to totally disengage the clutch and it had street/strip material on it not sintered material. It was in my car for 20 years till I had to have it relined. I sent the clutch and P Plate to Hays and they completely rebuilt both pieces for under $80 I couldn't believe it.
 
Do you have a fuel pressure gauge on it?
 
yellow rose said:
Ahhhh, yeah, that would be GHEY!!!!
Click to expand...
You keep believing a 4sp is the end all. lol I bet a lot of auto's have blew right past you. lol
Same engine same chassis an auto with a stall convertor wins EVERY time.
 
As much fun as banging gears is, an automatic can shift in milliseconds, compared to tenths of a second for a stick.
 
I’m a manual trans fan myself. I love bangin gears and dumping the clutch pedal. Moving away from stock manual transmissions really help a race effort.

The op doesn’t have a race car.
 
rumblefish360 said:
I’m a manual trans fan myself. I love bangin gears and dumping the clutch pedal. Moving away from stock manual transmissions really help a race effort.

The op doesn’t have a race car.
Click to expand...

Totally in agreement with the fun factor, and no, the OP doesn't have a race car, thread got a bit sidetracked. My bad.
 
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