Looking for advice/tips

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DDS74

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So I'm looking for some advice on my set up and my launch.

I'll ask about the launch first. I'm running cal tracs on my 383 powered dart and just using a 2-step to launch. In my research about launching, most people say to go just off idle, what do you mean by that, are we talking like 1,000 1,200 rpm or like 1,800-2,200 rpm? I idle my car around 1,000 rpm.

Next is a bit more of a technical question. As stated before I have a 383 in my car and I currently have a performer rpm intake on it, which is a dual plane, would I see much benefit going to a M1 single plane?

The specs on the motor; 383 punched .030 over, stock bottom end, Indy 440ez heads with no porting, and the cam is a comp solid roller .576/.582 lift at 248/254 at .050 (here's the specs Xtreme Energy 248/254 Solid Roller Cam (3 Bolt) for Chrysler 383-440)

The car is a dedicated race car with 4.30 gear so no worries about street manners
 
Personally I would never launch off idle but are a million different answers to launching a car but only one good one. Keep good detailed records on what you do or change. You will find the answer you are after.

As far as the manifold on a bracket car, you run against your own number so don’t break the bank looking for a tenth. IMHO.
 
If you are bracket racing try launching at different rpms that will give you the best times while staying consistant because that going to help you go rounds. As far as intake for dedicated race I would use the M1
 
I always footbraked, so I can't offer specific advice on launching with a 2-step. However, major reasons to launch with a 2-step are to maintain consistent launch RPM while keeping that RPM low enough to keep the car from overcoming the brakes and creeping. (With a trans brake, you're "locked" in place by the trans and can also go much higher on the launch rpm without concern for "creep" in the staging beams.) Launching a significantly different RPMs may also require some carb tune-up adjustments, especially if you don't have a trans-brake.

Your torque converter also affects how the car launches and what the car likes to launch harder/run faster. It needs to be matched to the rest of the combo for best results. Naturally a single plane intake will like a looser converter than a dual plane. But switching intakes can also affect the optimum carb tune!. I suggest sorting out the current combo before changing intakes.

But either way, in bracket racing it's much more important to have consistently good reaction times rather that fastest ETs. If you can try different launch RPMs to get better RTs and maintain ET consistency/predictability, it will go a long way to winning races. You can also vary RTs with staging techniques, front tire diameter and air pressure.

.....or do you have a stick???
 
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The car has a built 727 with a reverse pattern manual valvebody. I also footbrake the car too, i use the 2-step to make myself more consistent on the launch. The car is 3200 with me in it, typically runs high 11s in good cold air but in our Midwestern summers its low 12s. Am I doing ok time wise?
 
DDS74 said:
The car has a built 727 with a reverse pattern manual valvebody. I also footbrake the car too, i use the 2-step to make myself more consistent on the launch. The car is 3200 with me in it, typically runs high 11s in good cold air but in our Midwestern summers its low 12s. Am I doing ok time wise?
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You haven't mentioned the compression ratio, converter or tire size.

In my experience lower compression 383's with single plane intakes are dogs unless they have a bunch of gear or are in a light car.

I agree with K.O. Swinger, when Myron gives advice........listen.
 
When you launch off the two step, are you using a brake pressure switch or a button? The AMX I race has a transbrake now, but I used to launch with a two step and a brake pressure switch. The Carter AFB carburetor does not have enough pump shot to be able to foot brake the car. Some people like to launch having the converter flash, so they leave at a lower rpm. But most adjust there reaction time by starting line rpm. Alot of the bracket racers around here use a starting line control, that sets the rpm the same when staged, and it is adjustable to change their reaction times.
 
Funny, I used that exact same cam (the small block version) in my last 410 stroker, loved it....best was 10.57 in cold air with a big ole tail wind, lol.

I would try different launch RPM's and see what your car wants. I like to leave at ~2500 with my 408 and an 8" converter. My car will ET the best if I leave at 2000, but my RT is better if I leave at 2500.
 
I'd say the compression ratio is around 9.5-10:1, it still runs on 91 pump gas. The torque converter is an off the shelf 10" 3500 stall. I run the 2 step off a button.
 
DDS74 said:
I'd say the compression ratio is around 9.5-10:1, it still runs on 91 pump gas. The torque converter is an off the shelf 10" 3500 stall. I run the 2 step off a button.
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Then a purpose built torque converter will help u a few tenths if the rest of the combo is up to the task. What does it stall at now? Flash stall? Kim
 
DDS74 said:
The car has a built 727 with a reverse pattern manual valvebody. I also footbrake the car too, i use the 2-step to make myself more consistent on the launch. The car is 3200 with me in it, typically runs high 11s in good cold air but in our Midwestern summers its low 12s. Am I doing ok time wise?
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What is your typical MPH and 60 time?
 
Yea I agree with that, in previous years its cut a 1.75, that's why I'm trying to figure out this combo so I can consistently be in the 11s. What kind of cost is a custom converter, and what do they need, I don't have a dyno sheet for this motor. And as always money is always tight, especially when I'm trying to save up a to build a 440.
 
Trap RPM ? 3500 stall is too low for a 383, need at least 4500, probably 5000 stall.
 
Well it turns out that M1 intakes are quite hard to come by. So would there be any other single plane intakes that are recommended? Victor? Trick flow? Indy?
 
Have you googled Mopar manifold shootout? 1_2 It is a very comprehensive test on intake manifolds on a 383 Mopar. I would think you would answer all your questions
 
I’d like a description of the two-step/footbrake launch procedure.

My 3670lb B body went mid-low 11’s with a 383.
5400 stall, 4.56’s, 30” radial slicks.

I loaded the converter up to about 2000-2200, then it would flash to 5400 at the hit of the throttle.
60’ times in the mid-1.50’s, with a 1.51 best.
 
PRH said:
I’d like a description of the two-step/footbrake launch procedure.

My 3670lb B body went mid-low 11’s with a 383.
5400 stall, 4.56’s, 30” radial slicks.

I loaded the converter up to about 2000-2200, then it would flash to 5400 at the hit of the throttle.
60’ times in the mid-1.50’s, with a 1.51 best.
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you forgot to mention the unported 906's. :thumbsup:
 
fishmens67 said:
you forgot to mention the unported 906's. :thumbsup:
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Right.
Really shouldn’t forget to mention those.
After playing with the seat angles and the profile on the backside of the valve....... they flowed as good as 235@.450 lift.

Heavy TRW pistons were used, along with a cast crank from a 400........ still externally balanced of course.

As for the OP’s combo....... the EZ heads and the 3500 converter doesn’t seem like the best match possible for a 383.
 
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At 3500 rpm and the cam he has (248* @050) it is a good match for the street. The recommended stall is listed at Comp is 3200. Track cars require a good bit more stall to make the most of it all.
 
DDS74 said:
Well it turns out that M1 intakes are quite hard to come by. So would there be any other single plane intakes that are recommended? Victor? Trick flow? Indy?
Click to expand...
Trickflow is excellent
 
8" 5000 or 5500 stall converter from PTC will run you around $900 plus shipping I think.
Your 60' should be in the 1.50's or high 1.40's
 
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