Air gap or M1 intake manifold?

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66340SEDAN

66340SEDAN

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I am working on a 1966 Valiant 340 4-speed. Which intake would you guys go with? I have mopar M1 single plane and a Crosswind (air-gap) dual plane intake. I have 4.10 gears, 510 lift cam, Hooker comp hedders, 2.02/1.60 valve heads, and a 650 Holley double pumper. I will be going with a mopar super stock hood scoop so clearance is not a issue. Should I run a carb spacer on either of these? Any suggestions would be great! :thumbup:
 
Depends if you want the car to be streetable or a racer? You'll need the rpms to be way up before you unlock any serious power out of the M1 (3000-8000rpm). I have a 501 lift cam and I switched from the M1 to an Eddy RPM Performer (dual plane) with a 1" spacer kit from FBO. There was a Holley 750 double pumper on the M1. The 650 Holley would be better on a dual plane intake.
 
The car will be driven on the street, also run at the track every now and then.
 
I run my duster quite often at the track and some street time too,i've got a Air Gap(Edelbrock)...and it performs very nicely for what i'm running 11.20's......
 
If you read the comparison tests between manifolds the Edelbrock RPM Air Gap makes more power through out the rpm range to 6000+ rpm compared to a single plane. You will only get an advantage from the single plane above 6000 rpm.

Also, a single plane manifold is less forgiving regarding carb sizing than a dual plane, which means you can run a larger carb on a dual plane without effecting driveability than you can on a single plane.
 
66340SEDAN said:
I am working on a 1966 Valiant 340 4-speed. Which intake would you guys go with? I have mopar M1 single plane and a Crosswind (air-gap) dual plane intake. I have 4.10 gears, 510 lift cam, Hooker comp hedders, 2.02/1.60 valve heads, and a 650 Holley double pumper. I will be going with a mopar super stock hood scoop so clearance is not a issue. Should I run a carb spacer on either of these? Any suggestions would be great! :thumbup:
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I'd do the RPM and a HMV super sucker (If you have the cash for one)

Otherwise, it looks good so far.
 
I would agree the air gap is a great choice for the street-but I disagree that an m1 loses alot of streeatable power compared to the airgap-including low speed tourque.In the tests/examples Ive seen and witnessed the rpm had a bit more tourque at the bottom and a bit less h.p. at the top from 2,000 to 6,000.There was very little real power difference between them,again the street manners are a different thing so that adds more to the deal and you already have the air gap so I would use it.If I didnt have an intake and found a m1 cheaper I wouldnt hesitate to use it either.
 
Are you limiting your choice to those two specific manifolds?

If you want low end torque along with get up and go, the Weiand Stealth is a far better choice!

The power band supported by the airgap and the M1 are more suited for higher rpm driving.
 
I forgot to mention that I have run several intake/carb combo's on small block MOPAR's over the years...

The best combo I have come across, by far, is the Weiand Stealth manifold (part #8022)... topped with a Holley 670cfm Street Avenger carb.

It will pin you to your seat off the line (or stop light), and pulls well to over 6500 rpm!

NO other combination has done nearly as well on any of my cars!
 
I'd recommend that if you're going to run the M1 use a 4 hole 1 inch spacer, it'll help the off idle response which may be a little sluggish with the M1 but then all hell will break loose.

Terry
 
mikesduster said:
what type of carb spacer would you run on a AIRGAP??...4-hole or open??
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Mike,i run the summit G1405 phenolic/plastic spacer on my air gap,you've seen it run nuff said......
 
TheDemonator said:
The power band supported by the airgap and the M1 are more suited for higher rpm driving.
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I would like to know how you can state that as fact when the Stealth has a wider RPM band than the Air Gap? Also the M-1 has excellent streetable manors for a single plane. It's just funny how well the single plane M'1 does so well.

He also said he has two intakes. The crosswind and a M-1 single. Thems the choices we got to choose from.
 
rumblefish360 said:
I'd do the RPM and a HMV super sucker (If you have the cash for one)

This combo seems to work quit weel for me - street and strip.
Click to expand...
 
TheDemonator said:
I forgot to mention that I have run several intake/carb combo's on small block MOPAR's over the years...

The best combo I have come across, by far, is the Weiand Stealth manifold (part #8022)... topped with a Holley 670cfm Street Avenger carb.

It will pin you to your seat off the line (or stop light), and pulls well to over 6500 rpm!

NO other combination has done nearly as well on any of my cars!
Click to expand...
Just curious - have you tried the Eddy Airgap compared to the Stealth on the same engine?
 
What size super sucker 4 hole carb spacer? 1 or 2 inch? Plastic/phenolic or aluminum? Phenolic/plastic spacer says it is for racing only? Car will be for the street and strip. Thanks, you guys have been a big help! :thumbup:
 
66340SEDAN said:
What size super sucker 4 hole carb spacer? 1 or 2 inch? Plastic/phenolic or aluminum? Phenolic/plastic spacer says it is for racing only? Car will be for the street and strip. Thanks, you guys have been a big help! :thumbup:
Click to expand...

I would suggest the 1" - 4 hole aluminum for your application.
 
I would recomend that you not bother with a spacer at all unless you can do some back to back dyno runs or runs at the track. Treat it as a tuning aid when you are trying to squeeze the last few ponies out.

Spacers just as often hinder performance as help, if it was an automatic improvement the intake manufacturers would build it into the manifold.
 
The Weiand stealth is better for the street ( in my observation ) because it's effective power band begins at idle... the others are just getting into their power bands @ or near 2000 rpm. And with an effective power band of idle - 6800 rpm (advertised), it is excellent in most all situations from out of the hole up to WOT. I have personally found that the top end of the power band may be a bit over rated though... it seems to peak at about 6200 rpm.

Those first few feet make all the difference in the world! (on the street)

I have indeed used an Edelbrock RPM Airgap manifold on the same engine... and if I were running at the strip most of the time, that would be my choice. But on the street, the Weiand performs better!
 
dgc333 said:
I would recomend that you not bother with a spacer at all unless you can do some back to back dyno runs or runs at the track. Treat it as a tuning aid when you are trying to squeeze the last few ponies out.

Spacers just as often hinder performance as help, if it was an automatic improvement the intake manufacturers would build it into the manifold.
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yes and no
Its a lot easier to add a 2" spacer than it is to machine 2" off the plenum to get hood clearance - and I think you will have to agree that the majority of manifolds are made with hood clearance in mind - except the new Super Victor or Indys.
 
Demonator;

I would love to try it out on back to back runs at the strip or better yet a dyno. But I just can't fund the cash for intake after intake. Though the advtertised rpm band is interesting enuff by itself, your early peak could be just part dependent. Not knowing what you have of course.

I'd like to know your opinion between the 2 intakes he has.
 
Hey 66340sedan; If you have a fairly loose converter, you probably wont notice much diffference between the Airgap and the M1. I havent noticed any difference on time slips replacing my Airgap with an M1, but then my shifts points are fairly conservative @6000. I have even experimented with an old LD 340 unit. I wouldnt replace anyone of the three to buy any either of the other two, not worth the $$ for my performance level.
 
My car has a 4-speed manual transmission. I also have a LD 340 intake but I was saving that for another day. Thanks again for all the great suggestions! Keith. :toothy7:
 
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