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1968 390/343 X heads |
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H60
AMC Apprentice Joined: Aug/09/2014 Location: Wister,Ok Status: Offline Points: 164 |
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Posted: Oct/25/2020 at 7:03pm |
Does the X mean anything, located just forward of front or rear spark plug depending on side? My original 390 has them and a set of 69 343 has them. Just curious. Mike
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Mike 1968 Blazerblue 390,4sp AMX
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SC397
AMC Addicted Joined: Apr/30/2009 Location: Michigan Status: Offline Points: 5428 |
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No. I don't remember seeing a pair without the X.
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PHAT69AMX
AMC Addicted Joined: Jul/07/2007 Location: West Virginia Status: Offline Points: 5905 |
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Think the AMC "X" Heads that might have something different have a cast-in X under the valve cover?
Don't remember for sure but did save this picture. Edited by PHAT69AMX - Oct/26/2020 at 5:12am |
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mramc
AMC Addicted Joined: Jul/12/2007 Location: United States Status: Offline Points: 3217 |
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NASCAR "X" heads , I had a set on my 390 AMX engine that got stolen. The intake and exhaust port should be 0.125 of an inch bigger then standard AMC heads. LRDaum
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LRDaum
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PROSTOCKTOM
Supporter of TheAMCForum Joined: Jun/20/2010 Location: Indiana Status: Offline Points: 2427 |
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It would be my guess that the X is actually an added structural component to the casting. There is not much in the way of support since the ports are below and a thin divider between them. It may have also been added to reduce the chill in that area when the heads are poured. Since thin areas tend to coll off quicker and if they cool to fast they crack.
Personally I think it's more of the above than anything to do with something "SPECIAL" Tom
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Molnar Technologies Full Service Dealer - Crankshafts & Connecting Rods
1969 AMC Rambler Rouge Race Car 1974 AMC Hornet Hatchback, Wally Booth Outlaw Nostalgic Pro Stock Race Car Project |
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Rebel Machine
AMC Addicted Joined: Jul/03/2007 Location: Western Il Status: Offline Points: 5118 |
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Years ago I had a '69 Javelin with a 290. It also had the 'X' cast in the heads. Doubt there's anything special about them. -Steve- |
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H60
AMC Apprentice Joined: Aug/09/2014 Location: Wister,Ok Status: Offline Points: 164 |
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I knew probably not special but they went to extra effort to out them there. Just curious. Thank guys love this forum. Mike
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Mike 1968 Blazerblue 390,4sp AMX
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Hurst390
AMC Addicted Joined: Apr/20/2008 Location: secret Status: Offline Points: 5752 |
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On the big x head(nascar).125 bigger maybe ported but I dont believe they are cast that way. I have a set here and they can be ported a little more than an oem casting..
Edited by Hurst390 - Oct/27/2020 at 4:11pm |
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SC/Hurst Rambler
11.62 120 100% Street Legal |
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