Air Gap vs. M1 Single Plane For Stroker

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Mean416

Mean416

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Hey guys, I have both an M1 single plane and an Air Gap on hand. Just trying to figure out which one will be faster. I'm kind of thinking the Air Gap. What do you guys think?

Here's my combo:

72 Dart, pretty stock body/chassis for the time being.
340 based 416 stroker, forged internal balanced Scat reciprocating assy. Dished forged pistons. About 10.5:1 with the zero deck and MLS gaskets.

Basically out of the box eddy heads. With a spring upgrade for the higher cam lift. A little mild port cleanup but nothing significant there.

Cam is a lunati voodoo hyd flat tappet: Duration @ .050 (Int/Exh): 242/252; Gross Valve Lift (Int/Exh): .533/.552; LSA/ICL: 110/106; Valve Lash (Int/Exh): Hyd/Hyd; RPM Range: 2500-6600;

I have 1.6 ratio Hughes rocker arms. So real lift is 568/588.

8-3/4 axle, 4.11 gears

727 trans, PTC 4200 converter
1-7/8 to 3.5 hedman huslers
750cfm race demon


This is primarily a street toy, go to the coffee shop, Friday drive to work kind of car. Will see very occasional strip duty but not that often.

So, which intake wins?
 
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I disagree. I’d run the RPM and use a spacer if possible. Nothing about the combo (to me anyway) says single plane usage.

For a single plane. IMO. The cam is small, the Edelbrock heads are stock on the ports, the car is heavy. I think the stall is a bit high for street duty. You didn’t say what size tire you have.

I like the gear ratio a bit and the extra rocker lift is a good move. That’ll help up top.

If the car was light weight, more gear & cam duration by 10*’s min. Then I’d do a single plane and I’d feel on the boarder line about it. I get this from reading last members combos and there intake swaps with more engine than what you have ether in the build minus the engine size or similar sized engines.
Performer rpm or M-1 intake
(Post 13 as well mentions a member)
M1 to Air gap
Double check the 11 second thread sticky in the racers forum.


UOP said:
A couple years ago when my car still had the 360 I was going to do a turbo setup so I swapped my RPM Airgap for an M1 single plane. Big mistake. The car lost 3 tenths in the 1/4 mile I could never recover, no matter what kind of tuning I did. The loss of torque was noticeable even on the street. It made the car feel sluggish down low.

IMO swapping to the RPM Airgap would be a good move.
Click to expand...

Compare test results number 2 (RPM) vs number 5 (Holley Strip Dominator which the M1 is a improved on copy) and compare the HP vs Torque numbers. The cam was a rather stout one on (IIRC) MM lobes from Comp Cams.
Dyno-Testing Small-Block Intakes - Induction Extravaganza - Mopar Muscle Magazine
 
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Street Toy - Definitely try the RPM. That intake is really good and I've run that and single plane on small blocks. The RPM was so much better around town over the Victor Jr.
 
In re to rumble, the 380 hp and up crate motors all used the m1 intake. How are the cam numbers to small when the crate motors came with 501 513 which is smaller than what the op has?
 
@Howard1784 The MP 360/380 has a Hyd. roller cam intake duration @050 of 230 IIRC or somewhere close to that. The lift is not important at this point. That particular engine worked well as a bracket racer engine with a high stall and gear vs a street engine. The OP’s engine has a cam 10+*’s larger. In this case the duration dictates the rpm range. The lift comes in later when running the car down the track where more lift helps get the valve into the area of better air and fuel flow that the head offers. It works better at high rpm. You also add in the ramming effect of the column of air at higher engine speeds. This is we’re lift comes into play.

If he had 4.56’s w/a 904 turning slicks in a 3K-lbs. or less weight car, etc…. I’d say go for the single plane. Slap an 850 cfm carb and 1-7/8 headers into 3 inch exhaust with 16-18 inch tubes and a 3-1/2 inch muffler dumping before the axle.
 
I updated my original post. I forgot to mention that I will be running 1-7/8 hedman husler headers. I currently have a race demon 750 carb.

Planning to run drag radials to try to hook things up.
 
I'd start with the Air Gap then test with a 1" tapered spacer and go from there. If it doesn't have the top end you want, the M1 might solve that. You should have plenty of low end grunt with either for the street.
 
Thanks everyone for the replies. I know my combo sits in a strange middle ground. Hopefully it's fast that's my main concern
 
rumblefish360 said:
@Howard1784 The MP 360/380 has a Hyd. roller cam intake duration @050 of 230 IIRC or somewhere close to that. The lift is not important at this point. That particular engine worked well as a bracket racer engine with a high stall and gear vs a street engine. The OP’s engine has a cam 10+*’s larger. In this case the duration dictates the rpm range. The lift comes in later when running the car down the track where more lift helps get the valve into the area of better air and fuel flow that the head offers. It works better at high rpm. You also add in the ramming effect of the column of air at higher engine speeds. This is we’re lift comes into play.

If he had 4.56’s w/a 904 turning slicks in a 3K-lbs. or less weight car, etc…. I’d say go for the single plane. Slap an 850 cfm carb and 1-7/8 headers into 3 inch exhaust with 16-18 inch tubes and a 3-1/2 inch muffler dumping before the axle.
Click to expand...

Makes sense. Ty
 
Because of the gears & hi stall, and 416 cubes [ not 340 ] I would run the M1. Numerically lower gears & lower stall, I would use the AG.
 
Man this is not an easy choice. I have not really had a street car this hot before so I'm not 100% sure what to expect.

I know I won't literally be at WOT all the time when driving on the street. I'm guessing that for most street driving, even given the displacement/gearing/cam, the AG will probably make more torque, probably up to about 75% throttle? But maybe in the outright high load/WOT to redline scenario the single plane will win.

I'll most likely end up trying both combos out. Thanks for the feedback!
 
I'm in the same boat, just swapping off my Victor W2 for a M1 W2 dual plane. Worst case scenario, it sucks and I switch it back. Using the car for more highway trips than I originally thought I might. Will post results.
 
cpearce said:
I'm in the same boat, just swapping off my Victor W2 for a M1 W2 dual plane. Worst case scenario, it sucks and I switch it back. Using the car for more highway trips than I originally thought I might. Will post results.
Click to expand...
Please do let us know the results of the swap. My 422 W2 build is almost ready to button up and I am torn between a M1 dual plane that I have on the shelf or looking for a single plane to use. Please PM me with your combo if it’s not a secret :thankyou:
 
SSG_Karg said:
Please do let us know the results of the swap. My 422 W2 build is almost ready to button up and I am torn between a M1 dual plane that I have on the shelf or looking for a single plane to use. Please PM me with your combo if it’s not a secret :thankyou:
Click to expand...
Look up my W2 408 build here on FABO
 
@Mean416 you say mostly street but you seem more concerned with which intake will be faster. The M1 in your combo will make more peak power. But I’m guessing you won’t turn enough rpm to take advantage of that and make it faster. The RPM will make more usuable power under the curve and not give up anything until about 6500. I say RPM for the desired USE and if it was a bracket car that saw a little street time I’d tune it to take advantage of the single plane.
 
I have a suggestion. Swapping out intake manifolds is a pretty easy task. TRY BOTH! I would suggest starting with the M1. Drive it for a few weeks, and see how you like it. Consider drivability in town and performance. Then swap in the AG and test again. You have an opportunity to do this since you already have both manifolds. Most of us would love to have that option. For this setup, I think it will be close. I think you will like the AG better in town and the M1 better when full throttle is applied.
 
Mean416 said:
Hey guys, I have both an M1 single plane and an Air Gap on hand. Just trying to figure out which one will be faster. I'm kind of thinking the Air Gap. What do you guys think?

Here's my combo:

72 Dart, pretty stock body/chassis for the time being.
340 based 416 stroker, forged internal balanced Scat reciprocating assy. Dished forged pistons. About 10.5:1 with the zero deck and MLS gaskets.

Basically out of the box eddy heads. With a spring upgrade for the higher cam lift. A little mild port cleanup but nothing significant there.

Cam is a lunati voodoo hyd flat tappet: Duration @ .050 (Int/Exh): 242/252; Gross Valve Lift (Int/Exh): .533/.552; LSA/ICL: 110/106; Valve Lash (Int/Exh): Hyd/Hyd; RPM Range: 2500-6600;

I have 1.6 ratio Hughes rocker arms. So real lift is 568/588.

8-3/4 axle, 4.11 gears

727 trans, PTC 4200 converter
1-7/8 to 3.5 hedman huslers
750cfm race demon


This is primarily a street toy, go to the coffee shop, Friday drive to work kind of car. Will see very occasional strip duty but not that often.

So, which intake wins?
Click to expand...
The cam wants the dual plane, the convertor/gear will use both but leans toward the m1...

I bet where you drive the most will dictate it, whether technically combo matched or not..will work better for you.
Choose.
 
Mean416 said:
I updated my original post. I forgot to mention that I will be running 1-7/8 hedman husler headers. I currently have a race demon 750 carb.

Planning to run drag radials to try to hook things up.
Click to expand...
Single plane for sure
Let me know when you want to sell$ the AirGap
 
You have both why wouldn't you try both and see which one you like.
 
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