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  #1  
Old 12-01-2007, 07:50 PM
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JDart270 JDart270 is offline
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Default 360 heads on 318??

ive got a 79 318 need to do some work on and ive been thinking about putting 1973 360 heads ive got laying around on it while im at it. i think either way ill have them ported and polished but which would be a better choice?
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  #2  
Old 12-02-2007, 12:37 AM
dodger1 dodger1 is offline
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Why not? Bigger valves and ports to start with, and if you're gonna work the heads, do it on the 360 ones. You'll need cam, carb, and exhaust work to realize the potential, but they won't hurt anything in the meanwhile.
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  #3  
Old 12-02-2007, 02:22 AM
it's all dodge it's all dodge is offline
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If he decides not to to mill .040" off those 360 heads before putting them on there, reduced low end power, power in general, and sucky mileage is WHY not. If you're gonna put those on a 318, mill them, otherwise you will lose compression on an already low compression engine. The problem of less compression with the unmilled 360 heads on a 318 also gets worse with a bigger duration cam. There is also a certain amount that should be milled from intake side when milling that much from piston side- don't have that info on me now
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  #4  
Old 12-02-2007, 12:11 PM
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Depends on the power level of the 318 being sought. The 360 heads do not wake up the motor till later in the RPM range. The 318 just can't use all the port volume well unless your looking for a serious jump in power.

On a basic basis, the heads will work and provide more power. I'd rather pocket port the teen heads for a higher velocity head. This translates into more useable torque and a more effecient head with less cc's to start with so milling alot is not needed.

You also can port match them to the bigger windowed intakes for smooth flow and greater power.
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  #5  
Old 12-02-2007, 08:02 PM
dodger1 dodger1 is offline
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Just looked up chamber volumes for these heads - stock 318 is 63cc, stock 360 is 65cc. Would you need a .040 cut to lose 2 cc's? Would 2 cc's make a noticeable difference to the (stock) 318? I know later 318 cop motors used a 360 head, intake, and TQ on an otherwise stock motor.
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  #6  
Old 12-02-2007, 09:26 PM
70AARCuda 70AARCuda is offline
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Most stock 360 head chambers are closer to 72 cc unless they have been milled.
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  #7  
Old 12-02-2007, 11:05 PM
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i pulled my cop 318 heads off a cruiser. they had 1.88 1.60 valves, and adjustable shaft roller rockers. the guy said something about swirl ports too... i wouldnt put 360 heads on a 318. you end with 7.4 compression w/ 318 pistons.

my old 323(030 over 318) has always been a able street car powerplant. i have the MP factory 275 hp cam .430/.444, old edelbrock Streetmaster 5500max rpm SP mani with a octagon plenum center. tuned holley 600 vac sec. 24 lbs lightened 130 tooth flywheel. hedmen shorty headers. factory hei with tons of vacuum advance. 4 spd spins tires through first real nice and second.
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  #8  
Old 12-02-2007, 11:21 PM
dodger1 dodger1 is offline
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318's and 360's of the smog era mostly had 7.5 or so compression. Mark, those heads sound like they were 302 heads from a late roller-cam LA and yes they would have more compression than an earlier open chamber head
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  #9  
Old 12-02-2007, 11:53 PM
RacerHog RacerHog is offline
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J,
I would stay with the 318 heads and work on them....Good port, Valve job and gasket matching will go a long way. And give you good performance on a daily driver...Check out MRL Performances web site...Mike is great with 318's....

Just my 2 cents
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  #10  
Old 12-04-2007, 02:08 PM
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stock honest compression for a 70's 318, is really about 8 to one, some that were earlier 67 or 68 to 70 or so might be around 8.5 or 8.6. (they were advertised at 9.2 that it wasn't that high) The heads cc is about 68 cc, unmilled 69 318, '302 later model closed chamber, 63 cc unmilled, 72 915 J heads with 2.02 intakes put in, milled about .010" 71.6 cc..just my experience. None of these are magnums (much less cc head)
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  #11  
Old 12-05-2007, 10:39 AM
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Quote:
Originally Posted by dodger1 View Post
Why not? Bigger valves and ports to start with, and if you're gonna work the heads, do it on the 360 ones. You'll need cam, carb, and exhaust work to realize the potential, but they won't hurt anything in the meanwhile.
This is why.
http://www.geocities.com/alwest_83/318

Of course, all things build dependent. Stock 360 heads on a teen will not be the best idea until you really start looking for some serious HP. But, everybody will do what they want.
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  #12  
Old 12-05-2007, 11:06 AM
dodger1 dodger1 is offline
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Rumble, I stand corrected. The info I quoted was from "How to rebuild your smallblock Mopar" which listed all the heads up to the 302 and gave those chamber sizes. I was under the impression that only the 915 head had a 72cc chamber.
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  #13  
Old 12-08-2007, 04:14 PM
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Im runnin 360 heads on my built 318 and yes i had .040 shaved off they work good for a 318...
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  #14  
Old 12-08-2007, 05:50 PM
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Quote:
Originally Posted by dodger1 View Post
Rumble, I was under the impression that only the 915 head had a 72cc chamber.
Many a 360 and 340 head had/has a large 72 or so cc chamber. Not the 318 heads, unless they came with 360 heads like the 4bbl. packages.
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  #15  
Old 12-12-2007, 11:36 AM
mark7171 mark7171 is offline
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dodger-- yes, they were donated "302" cop heads.

the 302, 1.88/1.60 is perfect for the 318 bore fill. with the 3.94" bore it doesnt make the 2.02" intake valve spec cutoff. that cut is 4" .... those factory iron adjustable rockers(on a oil roller shaft) are million mile at least ..per police /municiple technician. the iron interceptor 318 "302" is a peppy street combo. i have my 323" behind a 4 spd with 3.23 gears. i figure my compression at 8.9 to 1 cause my pistons. holley 600 on a streemaster SP intake. mopar HEI with GM modual. i love the way it drives with the .430/.444 cam MP 275hp cam, and the old streetmaster single planes. small intake ports are 318 size, and my secret to winding through the gears. 1st can be soft clutched into a smoke show, or the perfect preload away from a sub 2 sec 60 ft. chips second as needed. somethimes even 3rd. fishtail around corners are easy as , slowing below synchro let it mph for 1st gear. then entering 1st around a corner, preload engine while letting the clutch out. makes cool wide fishtails. now for figure 8 's burnouts , and doughnuts...blah blah..

probably only a 14.5 seconds or so car in quarter. is that fast? or just fun cause i control the stall speed?
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  #16  
Old 12-13-2007, 04:18 AM
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enginemasters.com winter 2006 volume 9 no.4. built a 415hp 318. Problem is the stock piston is low in the cylinder. A quick fix is for flat top pistons to get some compression back and the motor will wake up. Here's an abridged version of that build. .040 overbore, KB 167 flat-top pistons and minor block decking for a true zero deck. 360 heads were machined for 2.02 intake valves and milled until 60cc chambers remained. Comp cam XE275HL 231/237 duration @0.050, 0.525 lift with 110 degree lobe separation with 1.50:1 rockers. Comp 972 single springs 1.750-inch for 140 lbs on the seat and 310 over the nose. Edelbrock performer airgap (milled to match intake ports of machined heads) with Mighty Demon 750-cfm carb. TTI's small block headers for exhaust. 394ft/lbs @ 4800 rpm, 415hp @ 6200 rpm. During build they changed to 1.6 rockers and power actually dropped, going up in ratio with a high ramp cam doesn't always work the way you think it will. I know this is a long winded reply but this is the best article I can think of and I'm a pack rat of car magazines with a great memory. Good luck
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  #17  
Old 12-13-2007, 01:45 PM
mark7171 mark7171 is offline
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comp cams and TTI setups start to get expensive quick.

the top end needs to be matched, i totally agree! i like the factory engineeredparts like : adjustable rockers, 302 heart shaped heads, MP cams, 4 speeds, exhaust systems with mufflers.

that xtreme cam is way too much. its like a race cam but a lil' tamer. you will need more gear too. witch kills the fun on the street.

i like around 110 #'s at the seat for my drivers.
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  #18  
Old 12-13-2007, 06:25 PM
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Quote:
Originally Posted by tenchu80 View Post
enginemasters.com winter 2009 volume 9 no.4. built a 415hp 318. Problem is the stock piston is low in the cylinder. A quick fix is for flat top pistons too get some compression back and the motor will wake up. Here's an abridged version of that build. .040 overbore, KB 167 flat-top pistons and minor block decking for a true zero deck. 360 heads were machined for 2.02 intake valves and milled until 60cc chambers remained. Comp cam XE275HL 231/237 duration @0.050, 0.525 lift with 110 degree lobe separation with 1.50:1 rockers. Comp 972 single springs 1.750-inch for 140 lbs on the seat and 310 over the nose. Edelbrock performer airgap with Mighty Demon 750-cfm carb.
TTI's small block headers for exhaust. 394ft/lbs @ 4800 rpm, 415hp @ 6200 rpm. During build they changed to 1.6 rockers and power actually dropped, going up in ratio with a high ramp cam doesn't always work the way you think it will. I know this is a long winded reply but this is the best article I can think of and I'm a pack rat of car magazines with a great memory. Good luck
how much HP do you think my combo is making?
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  #19  
Old 12-13-2007, 09:43 PM
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That above combo is a nice set up. I don't know if I'd do a 360 head on top or want a ported set of 302 or Magnums instead, but there ya have it, HP baby! And the cam is still mild.
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  #20  
Old 12-14-2007, 10:39 AM
mark7171 mark7171 is offline
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do you think im past 300hp ? it is a factory engineered combo for sure.


the way it breaths through the 318 streetmaster intake as it revs past the mid range is pretty exciting. the streetmaster intake has the 318 head 302 's port diameter to so its a match. the 600 holley is tuned with a good secondary spring and throttle blade position. pwr brakes(with modern one way valve added) and PVC on speparate vacuum ports, with a sealed crankcase.

the nostalgic sound is awesome .430/.444" lift cam through walker turbo 3 chambers mufflers. high velocity healthy sound that makes you think its badder than it is.



----you weren't referring to the XE274 as a mild cam? were you?
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  #21  
Old 12-14-2007, 09:19 PM
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MArk, are you asking me if the XE274 is mild? If so, then I answer, yes, absoultley so. Grandma has a bigger cam in her daily driver.

Can it make some real nice street power? Hell ya!!!
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  #22  
Old 12-15-2007, 12:16 PM
RacerHog RacerHog is offline
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Mark,
I think your looking at about 290Hp to 325Hp, Everything being up to snuff.
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