318 4 bbl and intake upgrade

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Dan the man said:
A 500 cfm is plenty for a stock 318. A 750 is way to big for a 318, the 340 intake manifold would cause port mismatch. The op said that his 318 is stock. Go with a weiand action plus intake manifold and a carb spacer and a edelbrock 500 carb. Also go with a good flowing exhaust system, a 2 1/4" system is fine
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Follow this advice and you’ll loose power.
RustyRatRod said:
I think "millions" was an appropriate number, don't you?
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I’d say like McDonalads did in the ‘70’s.
 
318willrun said:
I did an intake "swap" test on a 1976 318, 100% factory assembled stock short block. The stock '76 318 heads with a little bowl work. Summit cam (.455 lift). Stock converter and 2.76 gears.
'73 340 Cast vs Weiand Action Plus vs Holley Street Dominator. Here is the order they finished.
  1. 340 cast intake both ET and MPH
  2. Followed very very close by the Action Plus
  3. and a tight 3rd place was the Holley Street Dominator - with the 318 size ports.
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Thanks! For years I have been saying the cast iron intake is an excellent choice but constantly got **** on and called a know nothing idiot. But yet it is proven again….


Like triple R said…..
 
92b said:
Port mismatch matters. Port mismatch doesn't matter. Both are blanket statements that have exceptions. Not saying in this case it will matter but in some cases it does.
Chrysler did a lot of things based on the constraints at that time. Such as cost, availability, time, emissions, politics and performance to name a few. That caused a lot of compromises to be made. I don't think that just because Chrysler did it that way means it couldn't be done differently or even better. The OP has lots of options.
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I agree with all of that. I think as the combo gets more racy, the mismatch will matter more. On a stock or mild engine, I don't think it will ever make a difference.
 
318willrun said:
I did an intake "swap" test on a 1976 318, 100% factory assembled stock short block. The stock '76 318 heads with a little bowl work. Summit cam (.455 lift). Stock converter and 2.76 gears.
'73 340 Cast vs Weiand Action Plus vs Holley Street Dominator. Here is the order they finished.
  1. 340 cast intake both ET and MPH
  2. Followed very very close by the Action Plus
  3. and a tight 3rd place was the Holley Street Dominator - with the 318 size ports.
Click to expand...
Cool. Do you remember the details? I have a cast 360 intake I was thinking of using on a 360 instead of aftermarket aluminum. Is the 360 the same as the 340? How may versions of the cast iron 4 barrel are there and which are the best for performance.
 
92b said:
Cool. Do you remember the details? I have a cast 360 intake I was thinking of using on a 360 instead of aftermarket aluminum. Is the 360 the same as the 340? How may versions of the cast iron 4 barrel are there and which are the best for performance.
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360 TQ intake will perform just as well as the 340 TQ. Only real difference and why the 340 is preferred is the 340 does not have the EGR valve. As far as factory versions, the 340 4-hole and the TQ size are really what's out there from the late 60's to the mid 80's.
 
92b said:
Cool. Do you remember the details? I have a cast 360 intake I was thinking of using on a 360 instead of aftermarket aluminum. Is the 360 the same as the 340? How may versions of the cast iron 4 barrel are there and which are the best for performance.
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IMO, the one that outshines them all is the 71 340 Thermoquad intake with the totally flat plenum floor. The 72 has "bumps" cast in and the 73 of course has the EGR jets. I think the 71 is even better than the 68-70 intakes.
 
As early as a TQ intake you can get would be best. If it has an egr valve, just don’t put any vacuum source to it so it is left inoperable. Plug floor jets. Port match it as deep as possible yourself if you can.

Use a small TQ on 318’s for stock to mild performance, big TQ’s on everything else.
 
toolmanmike said:
If you want to be nostalgic. The old Edelbrock LD4B is a dandy intake. Kind of hard to find and not cheap for a nice one. Weiland makes one that works well with the smaller 318 ports as well. The LD4B works with factory air to if that's needed. I don't know about the Weiand though. Good used 600 Edelbrock carbs can be had for a hundred $$ or so and work well. The electric choke is a nice plus.
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Perfect port match for the 318s. Built by Edelbrock with a Mopar part number.
 
I had one of those (Minus a factory part number)
Very good intake.
 
People dont talk about these much but they really wake up a stock 2 bbl 318, and you use your stock cam and intake manifold.

Saves a lot of tear down with good results for those that want a simple performance boost without opening up a can of worms.

Edelbrock 1406 is jetted perfect for the stock 318 2 bbl cams, it gives the engine the fuel that it needs instead of running with an economy stock 2bbl.

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Please purchase a OEM 4bbl and compare them ….
 
The big thing here is to have some fun, squeeze some more performance out of your stock situation, learn some more about your setup, and get out and drive with a smile on your face.

Always fun to have the secondaries of the 4 bbls to play with as you are cruising around, regardless of how you get there.

Enjoy the hobby, it's all a good time.

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Melbourne Florida Super Swap/Show

☆☆☆☆☆
 
rumblefish360 said:
As early as a TQ intake you can get would be best. If it has an egr valve, just don’t put any vacuum source to it so it is left inoperable. Plug floor jets. Port match it as deep as possible yourself if you can.

Use a small TQ on 318’s for stock to mild performance, big TQ’s on everything else.
Click to expand...
Port match where the intake meets the head? The intake port is smaller than the head? Thank you
 
Dan the man said:
A 500 cfm is plenty for a stock 318. A 750 is way to big for a 318, the 340 intake manifold would cause port mismatch. The op said that his 318 is stock. Go with a weiand action plus intake manifold and a carb spacer and a edelbrock 500 carb. Also go with a good flowing exhaust system, a 2 1/4" system is fine
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The port mismatch thing is a myth. Yes they are are mismatched but it dont hurt a thing especially on a stock 318.
 
RRR stole my answer! Lol I would do a stock tq 340 or 340 manifold you can get them on here for cheap. I have 3 of them I think the cheapest one was like 50 bucks and a good thermoquad and have it rebuilt by our very own forum carb guy Dana!
 
rumblefish360 said:
Follow this advice and you’ll loose power.

I’d say like McDonalads did in the ‘70’s.
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He will not loose power, as he is going from a 2 barrel to a 4 barrel carburetor, that's 25 horsepower, dual exhaust around 20 horsepower, advance the ignition timing around another 20 horsepower, where's the lose? And Chrysler didn't build a million 4 barrel 318's. You guys think that every part you install has to be huge, simply not true.
 
The Dodge Diplomat was built from the 77 model year to the 89 model year. That's just ONE model car. How many of those do you think were equipped with the cop car package? Now, that would have been police, fire, EMA, boards of education, military and on and on. and that's ONE model. They were also available in vans and trucks. You don't think a million were made? You better think again.
 
RustyRatRod said:
The Dodge Diplomat was built from the 77 model year to the 89 model year. That's just ONE model car. How many of those do you think were equipped with the cop car package? Now, that would have been police, fire, EMA, boards of education, military and on and on. and that's ONE model. They were also available in vans and trucks. You don't think a million were made? You better think again.
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Police package was not available to the general public.
 
Back in the day when I was a poor college kid, I put a stock 340 manifold on a 318 with a Holley 650. Ran great, what increase in power with dual exhaust added too.
 
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