interchangeable heads?
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Senior User
Joined: Jun 2005
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From: Bethlehem, PA
interchangeable heads?
Hello, i have a 351M out of a 79 f150 supercab and a 400 out of a 78 f150 regular cab. i put the 400 in my supercab and ended up snapping a valve and ruining one head, but not damaging the cylinder wall.
i was wondering if i could safely swap that one head for one of the heads off of the 351M.
are the valves the same length?
which groove pattern would be better to use and would it make a difference?
thanks in advances for any help!!!
i was wondering if i could safely swap that one head for one of the heads off of the 351M.
are the valves the same length?
which groove pattern would be better to use and would it make a difference?
thanks in advances for any help!!!
Posting Legend
Joined: Sep 2001
Posts: 30,255
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Normally you would be better off using both heads from the 351M as long as they were the original OEM matched heads. With an old worn engine it probably does not matter. Engines from mass market rebuilders do not have matched heads.
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Senior User
Joined: Jun 2005
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From: Bethlehem, PA
Originally Posted by Matts72
You are better off just replacing the one bad head, opening the other side could create many other problems...
so what about the valves? are they the same?
im going to have to double check which valve retainer groove pattern is on which set of heads, but i think the valve retainer grooves are different between the heads
if this is the case could i just switch valves in one head to match?
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Post Fiend
Joined: Jan 2003
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From: Montana Territory
If the heads have not been rebuilt, then the valves are the same size. Head rebuilders often put in an oversize valve to compensate for machining out the seats. The valve locks should be the same, no matter what, I think they are the same for most ford engines.
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Posting Legend
Joined: Sep 2001
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You can find information on the valve train changes here:
http://home.earthlink.net/~bubbaf250/parts/parts03.html
http://home.earthlink.net/~bubbaf250/parts/parts03.html
Thread Starter
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Senior User
Joined: Jun 2005
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From: Bethlehem, PA
[QUOTE=Torque1st]You can find information on the valve train changes here:
http://home.earthlink.net/~bubbaf250/parts/parts03.html[/QUOTE]
Great link, found a LOT of useful info on there....
they talk about different retainers on that site, the solid ones and the ones that spin almost like a bearing, i noticed the rotating ones on my M heads...and on the site the said about different lengths....
which one would you think is better, the solid ones or the rotating ones?
i went on advanced auto's (car parts) web site and found one one size of valves for a 400 but two different sizes for the 351M, im guessing the different sizes are due to the rotating and none rotating retainers? im also guessing that if i mix heads and just use solid ratainers with single groove valves i found for the 400 i should be ok?
any thoughts on that?
http://home.earthlink.net/~bubbaf250/parts/parts03.html[/QUOTE]
Great link, found a LOT of useful info on there....
they talk about different retainers on that site, the solid ones and the ones that spin almost like a bearing, i noticed the rotating ones on my M heads...and on the site the said about different lengths....
which one would you think is better, the solid ones or the rotating ones?
i went on advanced auto's (car parts) web site and found one one size of valves for a 400 but two different sizes for the 351M, im guessing the different sizes are due to the rotating and none rotating retainers? im also guessing that if i mix heads and just use solid ratainers with single groove valves i found for the 400 i should be ok?
any thoughts on that?
