360 stock intake manifold on a stock 318?

-

victa15

Well-Known Member
Joined
Feb 27, 2013
Messages
224
Reaction score
47
Location
Tucson
I know aftermarkets are different but are stock the same size ports or will it make my 318 run like a dog. I picked up anther project and its a 2bbl. I want to switch to a 4bbl carb. Thanks
 
The ports on a 360 intake are larger than the 318 head ports. The air coming in will hit the material around the small head ports like a wall and cause flow issues.
 
probably still run better with a 4 barrel then the 2 barrel ....
 
Ok just like the aftermarket intakes. Thats what I thought. I didnt want to waste time pulling one off at a junk yard. Thanks of the info
 
Yeah The 2bbl on it is making it run rough and It boggs out as soon as I step on the gas. I have a few carters laying around. also do I have to change the kickdown linkage? I know the kickdown bracket is different
 
Those factory manifolds held their own quite well when tested against the aftermarket manifolds. Unless you're stuck on having aluminum. It also limits your carb choices since the stock manifold was spreadbore only.
 
The ports on a 360 intake are larger than the 318 head ports. The air coming in will hit the material around the small head ports like a wall and cause flow issues.

Somebody shouldda told Chrysler that because they built 318s with 360 intakes by the millions and they worked just fine.
 
Of the 4 sides of the port it lines up decently to the 2 main ones the roof and the center divider but not so well with the pushrod pinch and floor. On an average build not a biggie.
 
Of the 4 sides of the port it lines up decently to the 2 main ones the roof and the center divider but not so well with the pushrod pinch and floor. On an average build not a biggie.

so if i cant find a 318 intake a 360 one would be good? Im just doing stock. what about the kickdown? ive heard people having to extend it
 
What people fail to understand about this argument is this. Air is not being pushed into the intake port. It is being pulled. That means there will be no ill effects from the port mismatch, because there is a negative pressure at the port from the pistons pulling air into the engine. Air does not somehow mysteriously "pile up" at the intake port at the head, because of a mismatch. This is simply wrong thinking and untrue. It's an old wives tale.
 
Other than the old edelbrock ld4b I don't think there's an intake that fully matches the 318 ports. The edelbrock performer is half way between 360 and 318.

It's all compromises sure all these little things can add up hp and $$$ wise but no point stressing over it. Slap a 4 bbl on you will be glad you did.

Add a mild cam while at it you will be really glad you did.
 
so if i cant find a 318 intake a 360 one would be good? Im just doing stock. what about the kickdown? ive heard people having to extend it
I have a nice Stock 340 intake you can have for a good price. And not TOO far to ship.
 
I agree any factory 4 barrel intake will be way better than the 2 barrel set up. Go with what you kind find for cheap.
 
I have a ld4b but that's going on my 68 plymouth. the project is just going to be a daily driver and nothing special. but I do have a mild cam i was thing on putting into it.
 
I have a friend that has a 360 intake that will sell it to me for like 50 or 60 bucks. I might be able to get it for cheaper
 
I will guarantee you a mild cam....not too big, that intake, dual exhaust, and a recurved distributor you will NOT believe it "was" a 318
 
I will guarantee you a mild cam....not too big, that intake, dual exhaust, and a recurved distributor you will NOT believe it "was" a 318

Yeah I can tell the difference compared to the built 318 in my 68 plymouth to this one. lol
 
4 bbl is a good improvement to a 318.

But the biggest thing holding them back is the stock single exhaust. Make sure to run duals....
 
I've put the cast 360 4bbl manifold on 318's, and ALWAYS had it run great! Nice improvement over the 2bbl. I've had great luck with the TQ, and I've also put the adapter on there and ran Holley's, both run great.
 
What people fail to understand about this argument is this. Air is not being pushed into the intake port. It is being pulled. That means there will be no ill effects from the port mismatch, because there is a negative pressure at the port from the pistons pulling air into the engine. Air does not somehow mysteriously "pile up" at the intake port at the head, because of a mismatch. This is simply wrong thinking and untrue. It's an old wives tale.

This.
 
I have a friend that has a 360 intake that will sell it to me for like 50 or 60 bucks. I might be able to get it for cheaper
Maybe it's just me, but that seems more like 340 intake money. I think like half that is closer to right for a 360 intake. Then again, when you need one you'll pay what you need to.

probably still run better with a 4 barrel then the 2 barrel ....
And it's an improvement in flow over the cheap Performers anyway- can't see there being a big downfall unless you hate iron.

Tends to just make one run more consistently more completely through its range with a good carb. (no, a 280cfm 2 barrel's not)
 
the ports are different - but unless you're going out for some serious racing you'll never know - hit that intake, jam that 4 barrel on there, open up the exhaust and anything else you can do to make it more fun on the street - go have some fun, build it, experiment... eventually you'll undoubtedly pop for an aftermarket intake, but for now, make do with what ya got!
 
If you have dual exhaust and don't already have an "X" or "H" pipe that is another cheap power improvement you will feel in the seat of your pants!
 
short answer - yes. ..but more so with higher HP vehicles... that said, it is viable for you - why not/can't hurt right? EDITED: oops - sorry, thought you were the OP asking..
If you have dual exhaust and don't already have an "X" or "H" pipe that is another cheap power improvement you will feel in the seat of your pants!
 
What people fail to understand about this argument is this. Air is not being pushed into the intake port. It is being pulled.

Actually, Rob, on this one you are incorrect. There is not a "thing" called vacuum, in otherwords some invisible magic fluid, anymore that there is a thing called dark (lack of light) or something in a glass that replaces half full to "fillup" and "be" half empty.

The fact is that the pistons PUSH the air out of the cylinder during exhaust, and when the intake stroke is happening, atmospheric pressure from outside is pushing air into the empty, evacuated cylinder.

We talk about "suction" but in reality there is no such thing. What there REALLY is, is the atmospheric air pressure pushing into a void, an evacuated space.

But the more important point is that a reasonably "big" manifold such as a street 340/360 works well on small port 318 heads for a good solid performance "bolt on" jump.

These little guys DO also need a bit more cam, and of course exhaust as stated.

It's really too bad that "Ma" didn't make these engines more easily interchangeable, AKA 360 heads on a teen.
 
-
Back
Top