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291c Heads |
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69 ambassador 390
Supporter of TheAMCForum Joined: Nov/22/2009 Location: Peoria, AZ Status: Offline Points: 3539 |
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One intake and one exhaust if running a split pattern cam or just one valve if running a single pattern cam. I would not use the 70+ torque specs because those are for the bigger bolts. Because you are using ARP bolts I would add 10 and leave it. The clay test is not for the valve length it is because you are changing the cam and now a lot in the heads. Nothing is stock so check it. It takes two seconds to do because you already are doing the pushrod check. If you are running hydraulic lifters you need pushrods that are .010 to .030 longer than the checking rod at zero lash or if running H.P. anti pump lifters and zero lash you would add nothing to the length you figure. I like to have .100 or more piston to valve room at least so as long as it is that or more you are good.
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Steve Brown
Algonac, Mi. 69 Ambassador sst 390 84 Grand Wagoneer 69 Cougar XR7 65 Fairlaine 500XL 79 F-350 Super Camper Special |
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GREM
AMC Apprentice Joined: Feb/12/2011 Location: Colorado Status: Offline Points: 46 |
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Sorry I didn't clarify that I'm not changing the cam. Just the heads on the same 68 390 AMX motor with stock pistons so I can run a set of Headman dogleg headers. Mild RV cam (already in place with the square port heads) with the 51cc chambers & hydraulic lifters so I think you answered my questions. Ten over on the torque & .010 to .030 longer than 0 backlash on the pushrods... Thanks...
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69 ambassador 390
Supporter of TheAMCForum Joined: Nov/22/2009 Location: Peoria, AZ Status: Offline Points: 3539 |
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If you are using the same cam you are good there.
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Steve Brown
Algonac, Mi. 69 Ambassador sst 390 84 Grand Wagoneer 69 Cougar XR7 65 Fairlaine 500XL 79 F-350 Super Camper Special |
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amx39068
Supporter of TheAMCForum Joined: Feb/21/2008 Location: Arizona Status: Offline Points: 11576 |
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why would you need longer pushrods with 291C heads? They should have the same casting height as the earlier heads. The 70 and up block is taller but to the best of my knoweldge the heads are the same stud height as the earlier heads.
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Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development
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69 ambassador 390
Supporter of TheAMCForum Joined: Nov/22/2009 Location: Peoria, AZ Status: Offline Points: 3539 |
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Steve Brown
Algonac, Mi. 69 Ambassador sst 390 84 Grand Wagoneer 69 Cougar XR7 65 Fairlaine 500XL 79 F-350 Super Camper Special |
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Goodare 72 SST
AMC Apprentice Joined: Jan/09/2008 Location: Wisconsin Status: Offline Points: 147 |
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69 ambassador 390
You are correct, don't leave anything to chance check everything.
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1968 AMC Ambassador DPL - 1972 AMC Javelin SST - 1983 Honda Civic 1500DX CVCC - 28 Years Dealer Experience |
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amx39068
Supporter of TheAMCForum Joined: Feb/21/2008 Location: Arizona Status: Offline Points: 11576 |
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ah yes. With different rockers you will definitely need to check the pushrod length.
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Dan Curtis-Owner and CEO AZ AMC Restorations; Facebook: https://www.facebook.com/amcmusclecars/ & Curtis Real Estate Development
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SKeown
AMC Addicted Joined: Jul/30/2009 Location: Texas Status: Offline Points: 3085 |
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X2 Goodare, when reinverting an engine design, leave nothing to chance. Were often dealing with different cam base circle, lifter height, head & block surfacing, different rockers and valve stem height. There's too much at stake to take anything for granted. Details make the difference in you're outcome.
SKeown Edited by SKeown - Mar/28/2011 at 10:09pm |
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GREM
AMC Apprentice Joined: Feb/12/2011 Location: Colorado Status: Offline Points: 46 |
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Thanks for the feedback everyone! I'll heed the advice & check for clearance. I'll report back with the results in about three weeks when the motor is pulled & on an engine stand.
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beepbop
AMC Fan Joined: May/07/2009 Status: Offline Points: 17 |
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