Captainkirk
Old School Mopar Warrior
Somebody posted a link once regarding the different chamber sizes (in cc's) of the various 318/340/360 head chambers but that was on the old forum and I can't find it now. Anyone have it in their memory bank?
X head chambers?
- Thread starter Captainkirk
- Start date
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abdywgn
dismantler
Does this help?
Small Block Cylinder Heads Castings - Porting
Small Block Cylinder Heads Castings - Porting
Captainkirk
Old School Mopar Warrior
Yes, but oddly enough, they don't mention the '68-'70 X heads.
mderoy340
Well-Known Member
my X heads are 67CC 2.02 1.60 manley SS valves. It's best to cc the ones you have. After 40+ years and valve jobs who knows.
Locomotion
Well-Known Member
As cast, assembled 340 and 360 heads tend to be in the 68-72cc range, which is bigger than most "blueprint" specs. # of valve jobs, milling over the years and valve design will affect it.
Captainkirk
Old School Mopar Warrior
Reason I'm asking;
My '72 1.88 J heads were previously cc'd to 67 cc's. I have an untouched set of early 2.02 X heads I could use for the build if need be; stock X's should put compression in the 10:1 are, the J's will be around 9.75:1 as-is.
My '72 1.88 J heads were previously cc'd to 67 cc's. I have an untouched set of early 2.02 X heads I could use for the build if need be; stock X's should put compression in the 10:1 are, the J's will be around 9.75:1 as-is.
I've had 340/360 heads measure from 69-72 cc...
You don't know if there was any machining done to them before you get them, so you have to measure each head to find out...
You don't know if there was any machining done to them before you get them, so you have to measure each head to find out...
Captainkirk
Old School Mopar Warrior
The J heads were cc'd to 67cc's and had a mild porting job. The X heads are untouched, as-removed with a whole lotta miles on them. I have not measured the X heads.
perfacar
Well-Known Member
hi, usually most are about 5 to 6 cc bigger over min volumes. the X head is 63.3 cc, J head is 64.7 cc. these are set by mopar. different style valves will affect volume. nail head valve will make it smaller. it doesn't have the dish of tulip valve.
txstang84
Well-Known Member
Also consider: unless you replace the seats, when/if you grind them on the X heads, it will drop the valve farther into the bowl because they're already cut for 2.02 valves. That will increase chamber volume and hurt flow
those are minimum specs per nhra stock class....nothing to do with the real world....CC your heads...if you want to know what they are...
Lustle
Well-Known Member
I would CC the heads. That's the only way to get a guaranteed answer. Besides, if you're going to do any work to them, you will then have to mill the head to bring the compression back up anyways. So you'll want to CC them anyways.
Captainkirk
Old School Mopar Warrior
The 1.88 J heads were cc'd twice; first time when the engine was built years ago; they were all matched at 67cc's.
The 2.02 X heads have never been cc'd or touched. Just trying to figure out which heads to use on the new build.
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