M1 SP vs Air Gap

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The dual plane ran best when the deeper side plenum jets were 2 #'s bigger than the shallower side. I accidently stumbled across the idea when I happen to notice that the cylinders/plugs fed by the deeper side plenum 1/2 were colored lighter than the shallower 1/2!

Now that is a compelling thought! Below is a pic of the 340 I have sitting to the side that the stealth came off of. Maybe I am imagining things, but it appears there is more Carbon build up on the middle 2 (lower plenum) cylinders than on the outer 2 (upper plenum). Thoughts on that?

14.jpg
 
Based on my plug coloration and results, a square-jetted carb would run leaner in the lower plenum runners and chambers. A richer running cylinder would tend to be more carboned up but I would think ring seal would be more of a factor. Plug readings after a good 1/4 mile run, or after a few, and cut off before idling too much, which would contaminate the appearance, would be a better indicator.

It would seem that the lower lever would present a bigger plenum, which would reduce the vacuum signal and require slightly larger jets.
 
If you got a light combo that has good heads and that'll be running over 4200 most of the way down the track I think the M1 will go quicker, If the M1 doesn't make more top end power you probably don't have either enough cam, compression or head on the car to max the RPM out, but fact of business an M1 (modeled after the old Strip Dominator) will flow more air.
Most heavier dual purpose cars with automatics will like the RPM or Air gap better because higher average torque will out ET higher top end power because (if you think about it ) you utilizing more of the powerband going dow nthe track, particularly with steet stall type converters where the shift recovery flash RPM is below 4000.

I thought about keeping hte RPM I already had for my Rocky but with my particular combo I want to Take off some upper bottom torque without killing top end power....so I went with the M1.....it really depends on your App.
 
Most heavier dual purpose cars with automatics will like the RPM or Air gap better because higher average torque will out ET higher top end power because (if you think about it ) you utilizing more of the powerband going dow nthe track, particularly with steet stall type converters where the shift recovery flash RPM is below 4000.

Sounds like the more appropriate application for a stroker - which mine will be.

Verry valuable and interesting observations - Thanks all.
 
Dead Thread Revival Alert!! Has it ever been decisively determined that one is better than the other? And with the Trick Flow single plane coming out I believe we are in for a repeat of "one vs. the other(s)" Seems to me it all depends on each individual setup, along with a dash of real world and perhaps a splash of subjective, along with a smidge of the placebo effect?
 
I noticed the Trick Flow intake is now showing will be shipped come May of this year on Summits site. I assume the first batch sold like hotcakes, haven’t read of too many getting theirs yet.
 
Don't want to steal the thread,but since everyone is talking, just a quick question. I have an LD4B and would like to use it on a 340 with x heads. I'm going to run a thermoquad. Would I be better off to run an adapter or open up the intake so the TQ can bolt direct. I'm after low to mid range torque. Also, if I port match the intake to the heads, will it be the same as an LD340?
Thanks guys.
Cant help you with the TQ fitment, but make sure the LD4B will seal to the larger heads ports.
Wow, just noticed original date on this deal, hope everyone is alive, well, and still Mopar!
 
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Dead Thread Revival Alert!! Has it ever been decisively determined that one is better than the other? And with the Trick Flow single plane coming out I believe we are in for a repeat of "one vs. the other(s)" Seems to me it all depends on each individual setup, along with a dash of real world and perhaps a splash of subjective, along with a smidge of the placebo effect?
It 100% depends on the combo....nothing else.....each intake will shine in combinations that are tailored toward their respective "sweet spots".
 
Goggle [ Hot Rod ] Mopar small block intake manifold flow test


Good article Hughes engines helped sort out some info .
 
Your welcome. Based on the articles, the use of a MP-M1 single is probably not what most people want to use on there street car. I would tend to agree. The fact of the matter is the RPM-AG is such an excellent intake and even more so on heavy cars is shown on the dyno graph to produce more low end torque to help get you moving out of the hole quicker has shown itself apparent via many members here already.

Ive been asked the question regarding when is the switch a good move and that is a hard line to draw. Another member in another thread found the RPM-AG to be faster than the M1 with cleaned up but otherwise stock Edelbrock heads and a cam with a 260 @050 intake duration.

While I believe him, his combo is the odd one out of what I normally see. Prior to reading his response, I would have made the blurry cam line at/around mid 250’s @050. And it is blurry because the rest of the engine combination can vary on a huge level and this is before we even discuss the rest of the drivetrain or the cars suspension set up and weight.

In the MP speed tips section, the information there is good and valid “For the time period of print” to be known to work and work well. While I would not support the use of a six pack over a good 4bbl intake, the best at the time, but out of production was the LD-340, which MP did sell over there counter with a Chrysler part number, once it was no longer made, they naturally sold there own “Best Intake”, the 6 pack. But the 6 pack is still a dual plane intake powering a car into the 11’s. That normally takes a cam in the 250 @.050 area under OE engine displacements.

Here is a good way to look at a single planes best time to use. Notice there operating rpm range. While it may be as low as 3K rpm, there normally rated rpm high end use is 6500 and better. If the cam you have in the engine your using isn’t making good hp at and north of 6500 rpm, your half way to a dual plane use.

Part two is how low of a rpm does the engine make power? Do you use it down there? Is the converter flashing below 4500? If so, your most likely using a dual plane intake at this point.

It has been long said that a single plane is for racing. And if your going to build a serious race car, then a single plane is what you want.

Yea yea yea you can bracket race very seriously with a freakin Cricket & it’s 4 banger.... I know, I know....
:rofl:
A lot of people here do really well with a rpm. Check out the racers top section stickies. The faster you go, the less use of a dual plane vs the more usage of a single plane takes place. Then you’ll also note cams are big along with the stall rating, higher gear ratio, etc....
 
All I know is that I want this at the strip:
3D130B42-6D9E-459D-BC14-D9CCC1B2B864.png
and I got these to try and hopefully get me there!
CED2995B-D7FF-44E2-A5F8-8040CB8877EA.jpeg
:lol:
 
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