643 and 347 heads?
Racer
Joined: Jul 2005
Posts: 387
Likes: 3
From: Indian Trail, NC
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
643 is alright one regardless of naysayers.
Stock #s are on top, bottom is after the first pass to see where they were at (lousy low/mid#s tell that) before anythign furher was done.
Wound up scrapping them and going aftermarket. For what he wanted by the time the grinding was done, big valves, etc etc it was less to go to a better head that would still outperform the LT.
Not a big fan of chopping a facotry head to death to get a big # imo it ruins the port characteristic.
For a mild or moderate build its worthwhile depending on use/$$. Not sure Im qualified to say that though.
Pretty easy to get the 250/180-190# out of them though. Would work great with a hotcam.
Stock #s are on top, bottom is after the first pass to see where they were at (lousy low/mid#s tell that) before anythign furher was done.
Wound up scrapping them and going aftermarket. For what he wanted by the time the grinding was done, big valves, etc etc it was less to go to a better head that would still outperform the LT.
Not a big fan of chopping a facotry head to death to get a big # imo it ruins the port characteristic.
For a mild or moderate build its worthwhile depending on use/$$. Not sure Im qualified to say that though.
Pretty easy to get the 250/180-190# out of them though. Would work great with a hotcam.
Last edited by cv67; Jun 28, 2009 at 01:09 PM.
Pro
Joined: Jan 2009
Posts: 686
Likes: 4
From: Austin Texas
643 is alright one regardless of naysayers.
Stock #s are on top, bottom is after the first pass to see where they were at before anythign furher was done. Wound up scrapping them and going aftermarket. For what he wanted by the time the grinding was done, big valves, etc etc it was less to go to a better head that would still outperform the LT.
Not a big fan of chopping a facotry head to death to get a big # imo it ruins the port characteristic.
For a mild or moderate build its worthwhile depending on use/$$. Not sure Im qualified to say that though.
Pretty easy to get the 250/180-190# out of them though. Would work great with a hotcam.
Stock #s are on top, bottom is after the first pass to see where they were at before anythign furher was done. Wound up scrapping them and going aftermarket. For what he wanted by the time the grinding was done, big valves, etc etc it was less to go to a better head that would still outperform the LT.
Not a big fan of chopping a facotry head to death to get a big # imo it ruins the port characteristic.
For a mild or moderate build its worthwhile depending on use/$$. Not sure Im qualified to say that though.
Pretty easy to get the 250/180-190# out of them though. Would work great with a hotcam.
http://web.camaross.com/forums/showthread.php?t=411824
Pro
Joined: Jan 2009
Posts: 686
Likes: 4
From: Austin Texas
Saw that . . 
I'm with Lloyd though, I didn't see him as bashing anyone, just expressing some valid points.
I haven't touched the cross sectional areas yet on these runners - waiting to learn more, may take me decades .....
BTW, nice grinding work you did on a couple pics you posted.
I'm with Lloyd though, I didn't see him as bashing anyone, just expressing some valid points.
I haven't touched the cross sectional areas yet on these runners - waiting to learn more, may take me decades .....
BTW, nice grinding work you did on a couple pics you posted.
