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Shaft rocker head chamber volume |
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232jav3sp
AMC Addicted Joined: Jan/09/2013 Location: Texas Status: Offline Points: 2451 |
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Posted: Nov/28/2018 at 8:57pm |
I cannot find this info in my '69, or '70, technical service manuals. The '74 tsm I have gives chamber volume, but for the later hear.
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FSJunkie
AMC Addicted Joined: Jan/09/2011 Location: Flagstaff, AZ Status: Offline Points: 4741 |
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They switched from what they called the "quench head" combustion chamber to an open chamber in (I believe) 1972. They switched back to the original quench head design in 1977. The pistons were different for each chamber too. I'm not sure what the CC of each chamber is.
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1955 Packard
1966 Marlin 1972 Wagoneer 1973 Ambassador 1977 Hornet 1982 Concord D/L 1984 Eagle Limited |
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Greyhounds_AMX
AMC Addicted Joined: Nov/14/2009 Location: Kansas City Status: Offline Points: 1268 |
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My old Tripod site is still up, I measured a number of heads back then. That should all be here:
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1968 AMX 390 w/T5
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FSJunkie
AMC Addicted Joined: Jan/09/2011 Location: Flagstaff, AZ Status: Offline Points: 4741 |
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I think the 1982 and up 258 head is different too. The compression ratio is higher and the spark plugs are different so that usually means a different head.
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1955 Packard
1966 Marlin 1972 Wagoneer 1973 Ambassador 1977 Hornet 1982 Concord D/L 1984 Eagle Limited |
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232jav3sp
AMC Addicted Joined: Jan/09/2013 Location: Texas Status: Offline Points: 2451 |
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I ask because I've been thinking about getting a little bit more out of the 232 in my 69 American. I have a rebuildable 258 head from a 70s engine. I also need to upgrade the valve springs so it makes more sense to spring a head i can get more out of. It will get me into a 1.6 rocker to make the most of the cam, and the ports I believe, are slightly better configuration. From memory, the valve guide bosses do not protrude as far into the port. I have considered doing a turbo, but honestly don't want to get into the expense involved in adding one. I would rather rebuild this head, do some port clean up, remove the square edges from the guide bosses, asket match, and have it decked to bring compression up to 9 to 1. Decking will depend on what my engine's compresson is, currently. I never did measure anything when I replaced the cam a year-and-a-half ago. Having to calculate it based off of cranking compression. All of it might lead to a larger cam; which I am fine with.
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Greyhounds_AMX
AMC Addicted Joined: Nov/14/2009 Location: Kansas City Status: Offline Points: 1268 |
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Frank will tell you what we'd both recommend instead...
But if you're dead set on running a 70s head, go with bridged pivot. Also there's a machining detail that was left out of the production heads that was part of the original flow bench development. I'll have to dig a bit to figure that out again, but I'd think anyone running a 70's head should add that extra machining to get the most out of it.
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1968 AMX 390 w/T5
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232jav3sp
AMC Addicted Joined: Jan/09/2013 Location: Texas Status: Offline Points: 2451 |
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It's not that I haven't considered the 4.0 head... I just don't want to spend the money on one, nor do I want to redo my exhaust downpipe to mate to the 4.0 manifold. Then there's filling the casting holes with JB, when really I would prefer to have them welded shut, but, more money. I could always call around the local wrecking yards and get prices on them. Truth be told, I don't have the gumption to go to a "you pull it" and do it myself. Craigslist has been a huge swing and miss for AMC parts in East Texas.
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