360 heads on a 318 of any benefit?

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I'd go with the 360 heads, and cut a bit off the surface to keep the CR up. The Exhaust valve diameter can be made a bit larger than the stock 1.60" if the guy doing the work is good. There is a bit of extra meat on the exhaust valve, so .050" isn't too hard to come up with. Swapping to the 360 heads gets you the larger diameter without any worries.

Back cutting the valves means they take "cuts" on the stem side of the valve head that make the transition from stem to valve head smoothly, thus allowing better airflow into the cylinder.

Because the 360 heads have larger runners, porting on the intake side can be minimal. Knocking down the casting edges and radiusing the bowl area just behind the valve seat will do plenty. On the exhaust side, port matching to the header gaskets will get you a load of flow, just stay out of the water jacket. Currently I have a set of 360 heads on a 340, and the exhaust side is ported out to where its easy to see the back side of the exhaust valve. It would not be a stretch to get a pingpong ball jammed in there, if that gives an idea of the cross section of the port.
 
Magnum heads are the best performance head for a 318 that you can use without modifying them. They came on the 92-02 5.2 (318) magnums from the factory and easily make good power. You would just need some 7.650" hollow pushrods, AMC type lifters with an oiling hole in the center (come with aftermarket cams most of the time), magnum heads, head bolts, rocker gear, and a specific magnum type intake like the Edelbrock Performer RPM Air Gap for magnum heads. Be sure to have upgraded springs with an aftermarket cam though. I used the R/T Springs.

I have all this stuff on a 360, and man does that thing run. Since it has the stock 8:1 pistons, I probably don't even have 9:1 compression now...and I'm easily making around 375hp.
 
Oh crud, Hey Max, sorry I missed this;

Max340 said:
While it is true that the air will move slower for any given RPM, accelerating the car, and thus the rise in engine RPM, requires as easy a flow as possible. Realistically, the valve seat is the most restrictive part of the runner. Swapping the 360 heads onto the motor will allow faster cylinder fill due to larger valves. The real issue won't be airspeed in the runner as much as it will be the vacuum signal to the carb. I have done this swap, and never had a problem with it while I was running it.
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I never had a problem running 360 heads on a 318 ethier, however, the valve size and port size that lend a hand in the velocity at the low speed I was getting at. The vacuum signal to the carb will be preety much the same no matter what head or valve is used. How fast it drops may be something, IDK!?

But I did like the move I made to a 318 head on a 318 when the build was mild.


I'm sorry to disagree, but I must. Anytime a mismatch of port sizes occurs, there will be "reversion", which causes huge amounts of turbulance where the ports meet. It doesn't really matter if its a 318 head and 360 intake, or a 360 head and a 318 manifold. The mismatch will cause turbulance and the engine will not be making the best of the two parts.
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I didn't even consider this when I replied to what you wrote.
Theres a reversion in the system anyway. The big issue with the port mismatch like you said. Your right.

(Perhaps I should have read what you said better and a tad more thought before input.)



Certainly the heads should match the intake, and if I did not suggest that, I should have. Given the 360 valve size of 1.88", I disagree with the valves being too big for the 318. In fact, if the exhaust valve can be enlarged to a 1.65, or 1.70" that would be very effective. But thats just my experience, YMMV.
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Whats YMMV?

Otherwise, generaly speaking, I think the 1.88 is fine as well.
On the cheap, the stock valve will work in many cases. A back cutting can be done cheaply. Then again, new 1.88 can't be to bad now can they?
I also agree with the exhaust valve increase. You can get a 1.7 for a SB MoPar?
 
Dart Shawn said:
They arent Summit but Summit does sell them, they are mopar performance, they are "LA" replacement head castings.

http://store.summitracing.com/partd...4294908110+400172+4294840085+115&autoview=sku

I researched the use of 360 heads on a 318 and got mixed opinion's but seems to me that the compression ratio will drop considerably, I was looking at going with a stock rebuilt set of 360 heads but I couldnt deck the block or heads enough to bring up the compression ration with out tossing off the mounting surfaces for the intake. please excuse me if I do not know what heads are what, I just base my knowledge off of research I am a Chevy guy, but that doesnt mean I dont like Mopar, hell I even like Ford I just know most about Chevy.

Shawn.
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Those are bare and each. You would be deeper than a set of Edelbrock's with no valves, etc.

I have seen that some feel that a 2.02" valve is too big for a 318. That is not true but it is true for the 318 he's working with.
 
goldduster318 said:
Magnum heads are the best performance head for a 318 that you can use without modifying them. They came on the 92-02 5.2 (318) magnums from the factory and easily make good power. You would just need some 7.650" hollow pushrods, AMC type lifters with an oiling hole in the center (come with aftermarket cams most of the time), magnum heads, head bolts, rocker gear, and a specific magnum type intake like the Edelbrock Performer RPM Air Gap for magnum heads. Be sure to have upgraded springs with an aftermarket cam though. I used the R/T Springs.

I have all this stuff on a 360, and man does that thing run. Since it has the stock 8:1 pistons, I probably don't even have 9:1 compression now...and I'm easily making around 375hp.
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The heads that came on 85-91 318's are even better. They have the same swirl ports and combustion chamber as a magnum head but use old school shaft mounted rockers and oil through the head. They also came from the factory with roller cams. I would avoid the Magnum heads unless you can get a package deal cheap. All of your original stuff works with the 85-91 heads. To me, the magnum rocker set-up is a step backwards. I can only guess why the factory went that route....???
 
You know, all this talk about adequate port and valve size makes me wonder how the modern DOHC quad-valve engines retain decent port velocity and work in street applications. They effectively have almost twice as much port volume as our old 2-valve engines but they still aren't dogs on the low end (or are they...?). Or is it just that the 2-valve design isn't as bad compared to a 4-valve design as you'd expect?
 
MOPEkidD-3 said:
You know, all this talk about adequate port and valve size makes me wonder how the modern DOHC quad-valve engines retain decent port velocity and work in street applications. They effectively have almost twice as much port volume as our old 2-valve engines but they still aren't dogs on the low end (or are they...?). Or is it just that the 2-valve design isn't as bad compared to a 4-valve design as you'd expect?
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A 4 valve head has a similar port volume using 2 smaller intake and 2 smaller exhaust valves. The smaller valves increase velocity and using 2 each of the intake and exhaust valves increases volume.
 
Hmm... That makes sense. But wouldn't the velocity be pretty much the same as one big port, because the piston is still drawing in the same amount of air/fuel on each intake stroke?
 
MOPEkidD-3 said:
Hmm... That makes sense. But wouldn't the velocity be pretty much the same as one big port, because the piston is still drawing in the same amount of air/fuel on each intake stroke?
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not exactly, that thought is left behind on a multi valve engine. Think more along the lines of a swirl port head only doubled in the swirl area all over the place.
Super swirl, lol
 
No problem.

YMMV = Your mileage may vary = good way to say that too many variables are involved to give a specific answer to every set of circumstances.

We "cheated" the 1.6 valves to a larger size (about 1.67" if I recall correctly) by doing the face cut a bit farther out and doing the same to the head. The guy I had doing it showed me what he did, and it was essentially pushing the diameter out to the most the valve could cover without problem. Since we used the stock valves, we had extra meat to work with. Aftermarket valves could (I think) be purchased at 1.70", depending on what valves were used.

Part of what led me to this was the fact that "marine grind" cams tend to have a longer exhaust duration. To shorten the duration(to kill overlap), but get the same volume of gasses out, the valve had to be larger.

So I asked the guy how I did this without spending "big money", thus the resulting "cheat."

I actually like the smaller intake (1.88 vs. the 2.02) in the 360 head. I saw too many friends doing the "Chevy thing", and slapping "2.02 heads" on all the 350s and slowing the car down in lower RPM operation.

The vacuum signal would be a concern on larger carbs, if any.

rumblefish360 said:
Oh crud, Hey Max, sorry I missed this;



I never had a problem running 360 heads on a 318 ethier, however, the valve size and port size that lend a hand in the velocity at the low speed I was getting at. The vacuum signal to the carb will be preety much the same no matter what head or valve is used. How fast it drops may be something, IDK!?

But I did like the move I made to a 318 head on a 318 when the build was mild.



I didn't even consider this when I replied to what you wrote.
Theres a reversion in the system anyway. The big issue with the port mismatch like you said. Your right.

(Perhaps I should have read what you said better and a tad more thought before input.)





Whats YMMV?

Otherwise, generaly speaking, I think the 1.88 is fine as well.
On the cheap, the stock valve will work in many cases. A back cutting can be done cheaply. Then again, new 1.88 can't be to bad now can they?
I also agree with the exhaust valve increase. You can get a 1.7 for a SB MoPar?
Click to expand...
 
MOPEkidD-3 said:
Hmm... That makes sense. But wouldn't the velocity be pretty much the same as one big port, because the piston is still drawing in the same amount of air/fuel on each intake stroke?
Click to expand...


Nope! They will fill the chamber better due to a huge increase in actual valve area and intake charge velocity. Basically, you get the top end performance of a big valve head with no sacrifice on the bottom.
The only as cast 2 valve heads that I know of that are competitive against the flow numbers of as cast 4 valve heads are Hemi's.

P.S. If this was not true, nobody would be making four valve heads. It would be considered way too expensive to build by the manufacturers if they did not get a big increase in performance from them.
 
Max340, LOL @ YMMV. Thanks. Good post.

Dave, you make a good point. The 3 & 4 valve heads having smaller valves and skinnier intake tracks have super great velocity and super high flow charteristics and an area not allways larger but sometimes larger than a 2 valve head. (I split a hair there only due to the need of the head/valve area on a given engine)
But tend to out flow and speed the mix into the cylinder.

I can only guess that a head like this on our old engines is possible, but for surley to expensive at this point in time to do. It would be an interesting challenge to make and I wonder how they would do.

The head would have to be preety big. Probably as large as the small block HEMI heads made awhile back.

But now where really getting off topic.
 
I don't know if you guys have read about this, but in Bill Weertman's book Chrysler Engines 1922-1998, he talks about the 4-valve variant of the 426 Hemi design they were working on when Ford came out with the 427 Cammer. They made two designs, one with two cams in the block (to drive the 16 valves on each cylinder bank) and another with dual overhead cams. They were almost ready to start production when of course Bill France had to ruin all the fun and banned any OHC or 4-valve engine designs. There's no telling how much HP that engine would have made, probably around 750, maybe more.\

And yes, we should probably get back on topic.
 
The Doomsday Hemi? They don't call me Mopar for nothin'!

Dual overhead cam Hemi

A 426 dual-overhead cam Hemi was actually produced - two of them, in fact, and both were made in 1964. The DOHC Hemis were made to counter Ford's response to the 1964 426 Hemi, the 427 SOHC, but when NASCAR ruled against Ford's engine, there was no need for the overhead-cam Hemi.

Neither of the DOHC Hemis were ever placed in a car; one was destroyed, the other moved to the Kansas City area. (source: Muscle Car Review. Thanks, Stéphanie Dumas.) Recently, famed engine builder Larry Shepard told us that he has the A-925 cylinder head and other related parts, purchased from the late Dan Napp.

An article by Tom Shaw in Mopar Muscle went into more detail. The DOHC Hemi was project A-925, and it would need to be much more powerful than Ford's SOHC 427, but still rugged enough for racing - and able to conform to NASCAR's rules. Two possibilities were considered, according to Shaw - one using two cams positioned between the heads, in the "valley;" four valves on each cylinder were operated by lifters, pushrods, and lifters. This expensive setup was an unused contingency plan. Nearly as ambitious was an engine with aluminum heads, dual overhead cams, and, again, four valves per cylinder, with pent-roof chambers. (Chrysler had been working with four valve per cylinder engines for a never-completed Indy run in 1963.)

The dual-plane intake manifold had eight runners per side (Chrysler was into efficient and innovative intakes) and made of magnesium - but designed for a single four-barrel carburetor, as required by NASCAR.

The cams were driven by a cog belt, using external cog wheels at the front of the heads. Because the cams were directly above the valves, valvetrain mass was low, so the engine could rev high - a 7,000 rpm redline was specified, high for the era.

Shaw wrote that no DOHC Hemi ran under its own power; they were driven by an electric motor to check the valvegear. Research stopped in 1964 when NASCAR banned the SOHC 427 and Chrysler's own race Hemi. One DOHC Hemi still exists.

DOHC Hemi Update: Jon Field wrote that there was a third (at least) DOHC Hemi made — and that he owns it, a 301 cid aluminum-block-and-head engine with twin cams, two cam covers on each head (the plugs are between them), hydraulic tappets, brass valve seats, and four Weber two-barrel carbs (165 cfm each). He says the oil pan holds 10.6 quarts, and that the engine has stainless steel headers, and an aluminum intake; it is apparently functional and runs on regular gas. We don't have any information on where it came from and whether it's a Chrysler effort or an aftermarket modification. http://www.allpar.com/mopar/hemi/hemi.html

I have a mag around here somewhere!:read2:
 
Actually, many smaller 4 valve engines (the good ones) use variable valve timing to run larger ports and larger cams, but the valvtrain bleeds off duration and lift to get low speed torque. That is what the "VTEC" Honda monicker is. Nissan and Volkswagen also use VVT. Others use boost like Subarus. Ford uses a spare exh valve on some V8s, and 4 valves on others. 4 Valve engines typically have smaller camshafts (compared to comparable 2valve engines) in them too.
 
moper said:
Actually, many smaller 4 valve engines (the good ones) use variable valve timing to run larger ports and larger cams, but the valvtrain bleeds off duration and lift to get low speed torque. That is what the "VTEC" Honda monicker is. Nissan and Volkswagen also use VVT. Others use boost like Subarus. Ford uses a spare exh valve on some V8s, and 4 valves on others. 4 Valve engines typically have smaller camshafts (compared to comparable 2valve engines) in them too.
Click to expand...


Everything you said there is true, but you left out the latest Viper V-10's and you also left out the fact that Neons had more power than some of the VTEC Civics and the Neon ran a straight up DOHC head and there is also the little known fact that Chrysler has probably built more turbo cars than anyone!

Check out this article:
readingsmiley.gif
http://www.geocities.com/alwest_83/318.html
Mid 1980's non roller cam 318, rebuilt with stock crank and rods. Arp rod bolts added when the rods were reconditioned. Crank turned .010"/.010". Flat top cast pistons were used. After the block and heads were milled to true up, a 9.2 to 1 compression was achieved. The heads are the #302 swirl port casting from a 1987 318. The heads have the larger 1.88"/1.60" valves installed, competition valve job and were treated to a full port job. Intake is the Edelbrock Performer. Carb is the Holley #3310 750cfm vacume secondary. Headers are basic fit all 1 5/8" primary tube. Cam is the Mopar Performance P4452761 with .450"/.455"lift , 268/272 duration. timing was set at 35 degrees total for the dyno test.

330 horse power @5750rpm.

How does that sound? The exact motor was also dyno run with 360 heads installed and it produced 290 h.p. @5750 rpm. That shows how port velocity is so important. But...290 h.p. is no slouch for a 318. Most of the same information presented here can be applied to the 273.
back to home page

click to go to Mancini Racing
 
This is exactly what we found at the race track also, that the 302 heads from a 85-90 318 were faster than the 360 heads. And by about 40 HP which in your post the dyno showed. But we used the 1.78 intake valves instead and it made a good bit more Tq.
 
moper said:
Actually, many smaller 4 valve engines (the good ones) use variable valve timing to run larger ports and larger cams, but the valvtrain bleeds off duration and lift to get low speed torque.
Click to expand...

Indeed, the newer engines mostly. I was thinking more so of the older engines and the first early rounds of multi valve engines.



That is what the "VTEC" Honda monicker is. Nissan and Volkswagen also use VVT. Others use boost like Subarus. Ford uses a spare exh valve on some V8s, and 4 valves on others. 4 Valve engines typically have smaller camshafts (compared to comparable 2valve engines) in them too.
Click to expand...

Interesting, very. I'm a bit behind on new engine tech. Not much desire to catch up. (Must be getting old)
Doesn't Honda have a variable intake manifold. Something about a 2 in 1 intake? (For lack of better words.)
Someone told me they have an intake that has doors on the inside that open up (For lack of better words again) from a dual plane design to a straighter shot single plane design?
 
mopar340dave said:
Everything you said there is true, but you left out the latest Viper V-10's and you also left out the fact that Neons had more power than some of the VTEC Civics and the Neon ran a straight up DOHC head and there is also the little known fact that Chrysler has probably built more turbo cars than anyone!
Click to expand...

My Father in laws Father in law (God rest his sole) used to do some work for Chrysler back in the early days of turboing the cars. They started in with the turbos early and made some quick little cars. Big go cart like cars. LOL
The GLS and the GLHS come to mind.

Anyways, listing everyhead and reminding one of whats left out is a list that can grow. The automotive world is huge and around along time.

Good article by the way. Mr. West has had the page a looooong time and still, every now and again, someone discovers it and/or I intoduce someone to it. It also shows and repeats what Chrysler had said years ago when the did the same work and added the ported 318 head to there catolog. I remember the write up under the graph. "We found gains of 55 hp over the 360 head"

YIKES! 55 HP! Woo - Hooo!!!!
 
rumblefish360 said:
Interesting, very. I'm a bit behind on new engine tech. Not much desire to catch up. (Must be getting old)
Doesn't Honda have a variable intake manifold. Something about a 2 in 1 intake? (For lack of better words.)
Someone told me they have an intake that has doors on the inside that open up (For lack of better words again) from a dual plane design to a straighter shot single plane design?
Click to expand...

The intake you are thinking of is often referred to as an active intake. You don't have to go any farther than under the hood of my 2000 Concorde to find it.
 
NO kiddin. Surprise surprise, I had no idea.
 
Here is some info on it. This is an earlier version, using two throttle bodies, than my 2000 Concorde's single throttle body set-up.

Active Tuned Intake Manifold
The 3.5L has what Chrysler calls an active tuned intake manifold. It is an aluminum cross ram design with dual 48 mm throttle bodies, a separate plenum for each bank of cylinders and individual runners for each port. This configuration boosts both low and high speed torque as much as 15 lb.-ft. compared to a conventional manifold.

A special computer-controlled Manifold Tuning Valve (MTV) is located on a passageway between the split-plenums to adjust the plenum volume according to engine load and rpm. The MTV valve helps broaden the engine's torque curve.

The thermostat housing is located in the front of the lower intake manifold. The manifold has two ports for EGR (one for each side) and a screw-in PCV valve. The PCV valve has a very low flow rate because the engine produces only about one cfm of blowby up to 5,200 rpm when the engine is new, says Chrysler. But in an older high mileage engine, blowby may be more than the original PCV valve can handle. This may lead to oil sludging if the oil is not changed often enough.

The top half of the manifold can be removed to gain access to the fuel injectors, which are mounted on a plastic fuel rail assembly that plugs into the lower intake manifold.
 
Mine is 3.2L 24-valve SOHC engine that makes 225hp and 255pounds of torque, bone stock!
I also average around 27 or 28 mpg!
The car weighs over 3500 pounds and is very quick!
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MAN! I had one and a 99 Concorde. I keep killing those damn model cars. I do miss the mileage though. I drive a 400 in a '79 3.55 geared Magnum everyday.
 
Mine is rolling towards 130,000 miles and still runs like a top. I recently changed out the timing belt, water pump, hydraulic belt tensioner and all the pulleys with bearings.
It is one of the best cars I've ever owned. It has almost every option available and everything works.
So much for "The Modern Mopar Haters Club"!
I can't join in good concious!8)
 
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