340 Intake manifold recommendations

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C2ndLTpigeon

C2ndLTpigeon

Mopar or no Car!
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Looking for some recommendations on a good performing intake manifold for my 340.
Here are my specs.

71 340 .040 over.
Keith Black pistons KB243
Comp Cam 2705 270/270 Duration .468/.468 lift 110 centerline
360 heads 2.02/1.60
Stock crank, stock rods.
Hooker headers
904 transmission with stock converter
8 1/4 with 3.55's

I have an M1 single plane intake that is a W5 intake and before I drill it out I want to know if its even a good intake for my setup. If not I would like to see if their are some better options.
I also have a fresh built 340 Thermoquad that I spent a pretty penny on and I would like to run on this 340. Not to many spread bore intake manifolds and I wonder if there is some power loss using a square to spreadbore adapter.

Thanks!
 
Not sure single plane is right for you. I’m not sure what a stock thermoquad intake goes for, but as to performance you can get more out of them than most people would believe. I know I can buy a stock 68-69 340 intake for $100 and with a bit of cleaning and cutting the divider down run mid 11’s. They are heavy, but pretty cheap and can make enough power to make you go 8 3/4 shopping.
 
I have a thermoquad intake but it is a 73 manifold. The thermoquad came out in 71 so the older 60s intake you may be referring to is the older intake for the factory AFB. While the stock intake is heavy Its hard to believe the iron intake is the best.
 
C2ndLTpigeon said:
I have a thermoquad intake but it is a 73 manifold. The thermoquad came out in 71 so the older 60s intake you may be referring to is the older intake for the factory AFB. While the stock intake is heavy Its hard to believe the iron intake is the best.
Click to expand...

It took years for the manufacturers to come up with a better intake than the factory one.
The LD 340 is an aluminium version of the factory manifold.
 
I'd run a stock 340 intake before that huge single plane. While don't think an Air Gap would be overkill, unless you plan on upgrading the engine in the future, I'd consider it a waste of money. If you're buying new.....or used, unless you find a DEAL on an Air Gap, I'd just go with an Edelbrock Performer. They're fine intakes and will match your camshaft better, IMO than the Air Gap.
 
C2ndLTpigeon said:
I have a thermoquad intake but it is a 73 manifold. The thermoquad came out in 71 so the older 60s intake you may be referring to is the older intake for the factory AFB. While the stock intake is heavy Its hard to believe the iron intake is the best.
Click to expand...
I'd run hell outta the 73 intake.
 
I took the M1 back to Brian at IMM. He has a performer he can clean up. He van put a 100 bucks in port work to it and that way if I decide the TQ and the performer are not a good match I can use the airgap and 650 edelbrock I have on the 318. Just wanted to save the airfare for a future 360 I plan to build
 
That sounds like the Comp Magnum cam that you have.

Keep the TQ!!!!

You haven't stated your goal [ just fun driving, drag racing etc ] because that should be a factor in choosing the intake. Single plane intakes are for higher rpm; also stock c'ter & smallish 340 cubes are limiting factors.
So a dual plane intake is probably best. The combo is in between the Performer & the Performer RPM. If more street oriented I would use the Perf. More spirited driving & trips to the strip, I would use the RPM.
 
I believe the "2100" iron intake was copied in aluminum and it good with a spread bore carb
 
C2ndLTpigeon said:
I have a thermoquad intake but it is a 73 manifold. The thermoquad came out in 71 so the older 60s intake you may be referring to is the older intake for the factory AFB. While the stock intake is heavy Its hard to believe the iron intake is the best.
Click to expand...

A factory TQ intake is very good, and beats a lot of aftermarket intakes. Look at what "Stock" class racers run.
 
C2ndLTpigeon said:
I have a thermoquad intake but it is a 73 manifold. The thermoquad came out in 71 so the older 60s intake you may be referring to is the older intake for the factory AFB. While the stock intake is heavy Its hard to believe the iron intake is the best.
Click to expand...
I’d run the factory iron intake and block the egr port on the side and call it good. Because it is.
 
You deffinately DON'T need a single plane get yourself a Edelbrock Air-gap proven time and time again the best dual plane out there,ran it on both my 366 and 416 performed flawlessly :thumbsup: :thumbsup:
 
Because intakes perform 'flawlessly' does not mean it is best for the application....
The Perf & stock intakes work best in the idle to 5500 rpm range.
The RPM has a range of 1500-6500 rpm.
The OP needs to decide which one best suits his engine.
 
Bewy said:
Because intakes perform 'flawlessly' does not mean it is best for the application....
The Perf & stock intakes work best in the idle to 5500 rpm range.
The RPM has a range of 1500-6500 rpm.
The OP needs to decide which one best suits his engine.
Click to expand...
And with that in mind…… also, since you love to match the RPM range of products up so much…. The cam card specs below!

IMG_0575.png


IMG_0576.png
 
rumblefish360 said:
I’d run the factory iron intake and block the egr port on the side and call it good. Because it is.
Click to expand...
I do have a factory Intake, lucky it does not have EGR, I just hate how heavy they are. Did not think they were any good other then just being a factory intake.
 
Ok so a little more info. I drive my valiant daily with a 318, it has a huges whiplash and am currently using an Airgap and Edelbrock 600 CFM.
I don't need to source an airgap as I have one but would prefer to keep it for a performance 360 I plan to build in the future for my Dart sport.
The reason I wanted to use the thermoquad is for the fact that while most people think they suck, I think they are a cool design and would like to try and make one work. I tried running a TQ with the TQ manifold I have pictured below and it was just not happy on the high end. I also tried the TQ on the Airgap with a square to spread bore adapter and ended up going back to the Edelbrock.

The plan for the car is to continue to be a daily driver that I alternate with my dodge neon. I love driving the car and can care less if it costs me more fuel.
So it is a street car and I don't plan to take it to the strip unless its just for fun, but not competition.
I have just always wanted a 340 and I picked this core 340 up for a $100 and its a fun project and some would call it a waste to use it in a valiant but that's me.
I do also have plans to put my factory AC back into the car. Was hoping the 340 will have some more power and not feel like a slug running AC with a 318. I guess some may say my use of a 340 is a waste since its not being used for a Max performance build.

Here is the TQ I have, it comes back as a 340 MTX carb, I would like to use it as I spent $400 on it from a reputable seller that properly rebuilds them. He had also included metering rods and jets if I planed to use it on a 318, 340 or 360.
343555570_1380406112808461_7428647637406071950_n.jpg


343557525_267105399085417_8612594106565640468_n.jpg

Here is the stock intake manifold, If its actually decent I guess I could use it, but the down side is the weight.
343543164_609979284482955_9106133575025435163_n.jpg


Here is my 318 setup, I am using an Airgap and edelbrock 600 CFM. I could use this on the 340, but with a stock converter and city driving, the airgap kicks in at the later RPM
341695171_106483705761735_2121733628877230110_n.jpg


343490644_806020757798582_776803447251001964_n.jpg


I have the ability to get an edelbrock performer from Brian at IMM as he has one that needs to be hot tanked and I gave him back the W5 M1 I had and he would do a even trade. He can also expand the ports for about a $100 which is not too bad.
 
Ether way is a win. The factory intake and carb are a rock solid proven performer. IMO, the RPM-AG will make a solid 20 hp more as long as the carb is big enough not to show any vacuum readings higher than what the TQ would. In other words, is it enough carb?

The answer is probably yes, though a larger carb may give more power.
 
My vote goes to the Thermoquad on the factory iron intake with the factory linkage all as it should be. Choke even. No mods etc to make the kickdown and throttle work as is typical on a high rise intake, no need for spacer/adapters.
 
Rumblefish,
Post #18. Which engine peaks at 5800 rpm with that cam? It suits four engine sizes: 273, 318, 340 & 360.
 
C2ndLTpigeon said:
Ok so a little more info. I drive my valiant daily with a 318, it has a huges whiplash and am currently using an Airgap and Edelbrock 600 CFM.
I don't need to source an airgap as I have one but would prefer to keep it for a performance 360 I plan to build in the future for my Dart sport.
The reason I wanted to use the thermoquad is for the fact that while most people think they suck, I think they are a cool design and would like to try and make one work. I tried running a TQ with the TQ manifold I have pictured below and it was just not happy on the high end. I also tried the TQ on the Airgap with a square to spread bore adapter and ended up going back to the Edelbrock.

The plan for the car is to continue to be a daily driver that I alternate with my dodge neon. I love driving the car and can care less if it costs me more fuel.
So it is a street car and I don't plan to take it to the strip unless its just for fun, but not competition.
I have just always wanted a 340 and I picked this core 340 up for a $100 and its a fun project and some would call it a waste to use it in a valiant but that's me.
I do also have plans to put my factory AC back into the car. Was hoping the 340 will have some more power and not feel like a slug running AC with a 318. I guess some may say my use of a 340 is a waste since its not being used for a Max performance build.

Here is the TQ I have, it comes back as a 340 MTX carb, I would like to use it as I spent $400 on it from a reputable seller that properly rebuilds them. He had also included metering rods and jets if I planed to use it on a 318, 340 or 360.
View attachment 1716083557

View attachment 1716083555
Here is the stock intake manifold, If its actually decent I guess I could use it, but the down side is the weight.
View attachment 1716083558
Click to expand...

That 73 intake has constant EGR ports in the floor. If they are not clogged, they should be closed off. Your TQ base is a 73 340 Manual transmission carb, hopefully the rest of the carb is also. I always ran an Auto carb on an Auto trans, probably no big deal, but they are different. You should get "heavy" out of your mind. If the car is faster and runs better, what does an extra 20 lb matter except for the one time you lay it on the engine. What choke are you running? How in the world can a TQ dissapoint on the top end? When those secondaries open up, it is exhilarating to say the least. Do you have the secondary spring adjusting tool? Are the secondaries opening? Are you using valve springs matched for your camshaft? Most people have no clue about carbs, a good early TQ is still probably the best production carb ever made. Followed by a Q-Jet, but it takes more work to fix them. Another carb most people will tell you are junk. How do those "Stock" and "Super Stock" class cars run so fast with those junk carbs?
 
Bewy said:
Rumblefish,
Post #18. Which engine peaks at 5800 rpm with that cam?
Click to expand...
A loaded question unless you have been there and done that.
Bewy said:
It suits four engine sizes: 273, 318, 340 & 360.
Click to expand...
And more actually.


FWIW, I just threw up that post for you and anyone else that might be wondering.
 
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