At nauseum..318 intake manifold to 340 or 360.

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nckennyb said:
The Holley Street Dominator intake has the four-barrel carb in the correct location so your linkages will work without modification if I remember correctly. I used one on my daughter's Barracuda with a 1969 318 with the original heads and it worked great.
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Agree.
I ran a single plane Street Dominator on the first 340 in my 67 Barracuda. As you say, the 2bbl linkage will work with single plane, and even with a 1/2" carb spacer. That's not a bad intake and if not altered has 318 size exit ports. There are a few different variations on the intake but sothing to fret over.

Lets see some photos of what's in there (under the hood) and people can probably make better suggestions based on what we see.
 
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The Holly Street dominator is an old school single plane intake. I have that manifold on my 318 and personally really like the way it performs. They’re getting harder to find though. The Edelbrock performer and the stealth intake are both good intakes for your 318. Not sure about the two barrel throttle linkage issue being mentioned earlier. I didn’t have any issues converting mine from a two barrel to a four barrel.
 
middleagecrisis said:
The Holly Street dominator is an old school single plane intake. I have that manifold on my 318 and personally really like the way it performs. They’re getting harder to find though. The Edelbrock performer and the stealth intake are both good intakes for your 318. Not sure about the two barrel throttle linkage issue being mentioned earlier. I didn’t have any issues converting mine from a two barrel to a four barrel.
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Nice. So the two I attached should work? As far as the linkage, you used the same linkage off your two barrel for your four?
 

The two intakes you listed will work fine as far as fitting and running but you will have to lengthen your kickdown linkage and modify the bracket that holds the throttle cable to bring it forward so it will clamp on the metal part of the cable housing or find a bracket for a 4 barrel car. You may also have to grind the area of the valve cover that fits down around the runners with those intakes or use an extra thick valve cover gasket. I have an LD340 on my Dart which is similar to the Weiand and I had to grind some relief for the intake runners so the valve cover would seat down right.
 
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Deltatech said:
Regular maintenance? Intermediate, lol
On this site putting together a 500HP 440 build in your garage is intermediate.
I recently did this swap for the 20th or 30th time. It costs about $1000. buying everything new.
Intake if no AC-Assault eddy air gap clone, the port mismatch is the boogy man. It doesn't make any noticeable difference on a mild 318 under 320HP.
if you have AC I'd go with the Edelbrock performer with the ac boss to mount the compressor built in.
Kickdown & throttle cables, Lokar style with brackets included. I bought 2 ,used one cable for kickdown and one cable for throttle and sold the extra bracket on ebay.
Carb-Edelbrock 1406 elec choke with a throttle adapter to make sure throttle and kickdown throw are 1:1
Don't start out trying to setup a holley double pumper, start with a Carter style Edelbrock carb it's easier to learn how to tune it and how it works. Plus it's better for a mostly stock cruiser.
Before you throw away or sell your old carb, take it apart, clean it, possibly rebuild and learn how it works in the process. Get some hands on with it.
When you go to set the kickdown cable err on the tighter side, too loose burns up bands in a hurry. Just one trip around the block with the kickdown too loose can smoke the band, I've seen it happen.
Luckily they are cheap and pretty easy to replace.
If the lean burn smog system is still on it your going to want to change out the ignition box. and possibly the distributor because some of the smog dizzys have too much total spark advance built in and the curve is terrible. It's easier to get this conversion kit.
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You've ran the linked intake with no issues before? Seems to be of good quality, but don't want something that will crack on me lol. Just verifying.
 
crackedback said:
intake-head mismatch on a street beater is a huge red herring.

Run whatever intake you have on whatever head you have. Lots of alum intakes recommended for a 340/360 have 318 size ports.
Ede 600-650 and make sure the kickdown is set up properly as @junkyardhero mentioned. REALLY important with an auto car.
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Everyone talks how horrible intake mismatches are & a few mention the factory uses or ones they've successfully used, but no one has ever mentioned what I read years ago on several forgotten blogs which said:
Mercury Marine( & maybe MM Racing, need research) ran mismatched intakes where, for instance they ran larger intakes on smaller head ports and saw more torque output. One quote stated BB Chev with Oval or Peanut port heads using intake for 820 square big port heads, and ran that with more torque output
Theory on why this works:
1)Large Mismatches. The size of port in head determines flow and with 820s large square port intake, therefore there is a lot of dead air where it stacks up in the corners, But head only pulls A Column of Air the shape of the port, thru the intake and turbulence is less than everyone theorizes.
Thought I'd mention Plenum Theory also allows air pulled from larger volume & we know that works.
2) on combinations where match is close turbulence might mean more, however Fluid Dynamics show that flow of air thru a curved path, causes differences in air speed, faster when a larger radius(ever boated on a river? Fast side always outside of turn), therefore the shortside slower air speed (and less pressure?). So if top of intake portmatched(sides also) or close you might see no turbulence with a port mismatch at bottom of port , and might see a torque improvement from airspeed.

Using those theories I plan on no port match to the bottom of my 318 ports & hope to have a step of no more than 1/8 "(almost too big), maybe 3/16.

I'd like to see someone test these theories on a dyno to get real figures, but wonder if
318willrun doesn't have some experience there. Or NC Enginebuilder guy.

Also I have an original Torker Single Plane and now wonder if anyone can confirm my 2bbl kickdown linkage will work on it instead of using the LD4B & searching for linkage.
 
Woody500 said:
Everyone talks how horrible intake mismatches are & a few mention the factory uses or ones they've successfully used, but no one has ever mentioned what I read years ago on several forgotten blogs which said:
Mercury Marine( & maybe MM Racing, need research) ran mismatched intakes where, for instance they ran larger intakes on smaller head ports and saw more torque output. One quote stated BB Chev with Oval or Peanut port heads using intake for 820 square big port heads, and ran that with more torque output
Theory on why this works:
1)Large Mismatches. The size of port in head determines flow and with 820s large square port intake, therefore there is a lot of dead air where it stacks up in the corners, But head only pulls A Column of Air the shape of the port, thru the intake and turbulence is less than everyone theorizes.
Thought I'd mention Plenum Theory also allows air pulled from larger volume & we know that works.
2) on combinations where match is close turbulence might mean more, however Fluid Dynamics show that flow of air thru a curved path, causes differences in air speed, faster when a larger radius(ever boated on a river? Fast side always outside of turn), therefore the shortside slower air speed (and less pressure?). So if top of intake portmatched(sides also) or close you might see no turbulence with a port mismatch at bottom of port , and might see a torque improvement from airspeed.

Using those theories I plan on no port match to the bottom of my 318 ports & hope to have a step of no more than 1/8 "(almost too big), maybe 3/16.

I'd like to see someone test these theories on a dyno to get real figures, but wonder if
318willrun doesn't have some experience there. Or NC Enginebuilder guy.

Also I have an original Torker Single Plane and now wonder if anyone can confirm my 2bbl kickdown linkage will work on it instead of using the LD4B & searching for linkage.
Click to expand...


This is correct. You are always better off matching the intake to the head but IF you are going to have a mismatch, the head should be SMALLER than the manifold.

There was ONE engine combo where a small intake port in the manifold made more power on a bigger port in the head.

It was a big block Chevy. Everyone read the article and it became the sacred cow that can’t be gored.

In fact, in a podcast several years ago Darin Morgan said exactly that.

Yet the battle cry from those who have it tested it is to make the manifold SMALLER than the head.

That’s a flow killer. You can prove than on a flow bench inlet than half a hour.
 
Woody500 said:
Everyone talks how horrible intake mismatches are & a few mention the factory uses or ones they've successfully used, but no one has ever mentioned what I read years ago on several forgotten blogs which said:
Mercury Marine( & maybe MM Racing, need research) ran mismatched intakes where, for instance they ran larger intakes on smaller head ports and saw more torque output. One quote stated BB Chev with Oval or Peanut port heads using intake for 820 square big port heads, and ran that with more torque output
Theory on why this works:
1)Large Mismatches. The size of port in head determines flow and with 820s large square port intake, therefore there is a lot of dead air where it stacks up in the corners, But head only pulls A Column of Air the shape of the port, thru the intake and turbulence is less than everyone theorizes.
Thought I'd mention Plenum Theory also allows air pulled from larger volume & we know that works.
2) on combinations where match is close turbulence might mean more, however Fluid Dynamics show that flow of air thru a curved path, causes differences in air speed, faster when a larger radius(ever boated on a river? Fast side always outside of turn), therefore the shortside slower air speed (and less pressure?). So if top of intake portmatched(sides also) or close you might see no turbulence with a port mismatch at bottom of port , and might see a torque improvement from airspeed.

Using those theories I plan on no port match to the bottom of my 318 ports & hope to have a step of no more than 1/8 "(almost too big), maybe 3/16.

I'd like to see someone test these theories on a dyno to get real figures, but wonder if
318willrun doesn't have some experience there. Or NC Enginebuilder guy.

Also I have an original Torker Single Plane and now wonder if anyone can confirm my 2bbl kickdown linkage will work on it instead of using the LD4B & searching for linkage.
Click to expand...
On the Torker question, I did the exact same swap on a 318 years ago and don’t remember encountering any issues that weren’t easy to correct with the factory 2 barrel linkage. I’m sure you’ll get others to chime in.
 
Newbomb Turk said:
This is correct. You are always better off matching the intake to the head but IF you are going to have a mismatch, the head should be SMALLER than the manifold.

There was ONE engine combo where a small intake port in the manifold made more power on a bigger port in the head.

It was a big block Chevy. Everyone read the article and it became the sacred cow that can’t be gored.

In fact, in a podcast several years ago Darin Morgan said exactly that.

Yet the battle cry from those who have it tested it is to make the manifold SMALLER than the head.

That’s a flow killer. You can prove than on a flow bench inlet than half a hour.
Click to expand...
 
That step down from intake to larger port in head would tumble the air so badly it could never work, especially that close to the valve, & probably screw up AFR & cause tuning problems.
 
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