Moparchat - Home of MOPAR enthusiasts worldwide!



Go Back   Moparchat - Home of MOPAR enthusiasts worldwide! > Technical Forums > Performance Talk

Click here to search for Mopar cars and parts for sale.


Reply
 
Thread Tools Display Modes
  #1  
Old 06-23-2002, 06:22 AM
k13 charger k13 charger is offline
Inactive User
 
Join Date: Dec 2001
Location: cairns queensland australia
Age: 61
Posts: 8
Default head swapping

Can someone out there please give me some kind of an idea as to what performance gain could be had by simply swapping the heads on my 360 motor ( "J" heads ) with a set of 340 "X" heads. That being the only change. Surely the better compression and flow would have to do some thing positive for the horse power out put of the motor. Thanks from george
Reply With Quote
  #2  
Old 06-23-2002, 05:54 PM
pishta's Avatar
pishta pishta is offline
Senior Member
 
Join Date: Aug 1999
Location: Tustin, CA
Age: 55
Posts: 3,987
Default

The J heads were probably blueprinted at 65cc while the X's were 63cc. The 2.02 will hurt the low a little while helping the high if your J's weren't 2.02's to begin with.
Reply With Quote
  #3  
Old 06-23-2002, 10:25 PM
jimbo7074 jimbo7074 is offline
Inactive User
 
Join Date: Mar 2002
Location: Vancouver British Columbia
Posts: 167
Default heads

Those two heads share the same chamber and ports so the X head will flow only slighly better from what I have seen in articles when both were tested on the flowbench.As for the chamber cc's my stock X heads came in at 70cc's.
Reply With Quote
  #4  
Old 06-24-2002, 12:26 AM
1972roadrunner's Avatar
1972roadrunner 1972roadrunner is offline
Inactive User
 
Join Date: Mar 2002
Location: Garden City, Kansas
Age: 38
Posts: 1,919
Default

my dad said it depends on what kind of head you use, the way they flow, the valve sizes etc....

i like my J heads, just wish we would have had them ported more...oh well, i hate being on a budjet...
Reply With Quote
  #5  
Old 06-24-2002, 01:15 AM
k13 charger k13 charger is offline
Inactive User
 
Join Date: Dec 2001
Location: cairns queensland australia
Age: 61
Posts: 8
Default

Thanks for the feed back. I should have told a bit more of the story. The 360 engine at the moment is a plus 30 thou bore. The J heads are the 1.88 inlet sized heads. It has a cam that is supposed to be a 340 grind. On top it has a 600 vac sec holley and an edelbrock dual plane manifold. The only two things hindering it a the moment are. (1) the inlet is a small port performer manfold to suit a 318. and (2) it doesn't have pipes on it. Both of these things will be changed in time and with a bit of money. Can any body suggest some thing else that may be helpful with the performance of this motor Thanks from George. All feed back is welcome!
Reply With Quote
  #6  
Old 06-24-2002, 03:27 AM
jimbo7074 jimbo7074 is offline
Inactive User
 
Join Date: Mar 2002
Location: Vancouver British Columbia
Posts: 167
Default

If the heads are not ported yet,a good street/strip job would wake up the motor,also a performer RPM or Weiand Stealth intake would be better than the Performer.
Reply With Quote
  #7  
Old 06-24-2002, 06:40 AM
rumblefish360's Avatar
rumblefish360 rumblefish360 is offline
Moparchat Bronze member
 
Join Date: May 2000
Location: C
Age: 57
Posts: 11,120
Default

I'm with jimbo7074 on a porting of the heads. A mild upgrade in cam will boost the performance some more without converter hassles.
In the keeping it simple side....

1. Open air cleaner
2. Upgrade in ignition. Ethier MoPars Orange box or a MSD or equal ignition box.
3. Dual exhaust with an "H" pipe. Even cheap turbo mufflers will help wake her up.
4. A 650-700 cfm carb. You'll outstrip the 600 quick on a 340.
5.. 2.02's in the "J" head, pocket porting, new springs to match the new cam. (If desired)
6. In keeping the cam small, duration should not be large, according too Comp cams, after about 218 @ .050, a change in converter is recomended, but lift is something you can go crazy on. Which leads to use of 1.6 rockers. But now were getting expensive.
Comp has a Dual energy, split pattern cams, and there new Extreme energy cams that are also split. Hughes also has cams custom ground for them by Engle. Enjoy the sites.
http://hughesengines.com/www/hughesengines/ http://compcams.com/
Reply With Quote
  #8  
Old 06-24-2002, 10:22 AM
Dart Dart is offline
Inactive User
 
Join Date: Nov 1999
Location: Loveland, CO USA
Age: 54
Posts: 942
Default

On the head cc's: No way the J or the X heads are 63-65 CCs. More like 70 CCs. To compare, the Edelbrock Closed chamber heads are 65CCs. The larger valve heads my hurt you with your current combo. The velocity in the head will drop and you may not get as good of a mix. If you go with the larger valve heads I would make sure to go with the larger port intake as well.

With any of these changes the 600 will be ready for an upgrade. You miught think about a 750 Holley vac sec.
Reply With Quote
  #9  
Old 06-24-2002, 10:12 PM
pishta's Avatar
pishta pishta is offline
Senior Member
 
Join Date: Aug 1999
Location: Tustin, CA
Age: 55
Posts: 3,987
Default

blueprint CC's are what Mopar designed them to be, not what they actually are. The same reference has the 273 solid lifter heads at 57! The fast burn 318 heads are 62.6, still smaller than the edelbrocks. They also have the 318 police at 75.1, that sounds big.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Swapping Four for one Eggman Vintage MOPAR chat 1 12-13-2010 10:22 AM
Swapping a 360/727 for a 413/a-833 PW Performance Talk 3 02-23-2003 10:49 PM
V-6 to V-8 Swapping DAKOTAX Dakota Truck Forum 4 04-09-2001 07:17 PM
Head Swapping Head Crash Performance Talk 6 01-25-2001 07:43 AM
Swapping a 2.5 for a v6 dclifford Jeep Chat (Wrangler, Cherokee, etc...) 2 01-22-2001 05:34 PM




All times are GMT -4. The time now is 06:15 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
. . . . .