Help! Cracked head?
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Joined: Mar 2008
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Gary,
So what I am reading is that you basically have two engines with (maybe) two good heads between them, right? I would pull the two heads I thought were good and get them checked out, then put them on the "built" engine and be done with it.
All you would be out is the gaskets and getting your heads checked.
I have done the "replace the blown head gasket and hope thing" before on a 400. It ended up that the head was cracked, resulting in me hunting to find a new '71 400 with nonsmog heads for my truck.
Robert
So what I am reading is that you basically have two engines with (maybe) two good heads between them, right? I would pull the two heads I thought were good and get them checked out, then put them on the "built" engine and be done with it.
All you would be out is the gaskets and getting your heads checked.
I have done the "replace the blown head gasket and hope thing" before on a 400. It ended up that the head was cracked, resulting in me hunting to find a new '71 400 with nonsmog heads for my truck.
Robert
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FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
Gary,
So what I am reading is that you basically have two engines with (maybe) two good heads between them, right? I would pull the two heads I thought were good and get them checked out, then put them on the "built" engine and be done with it.
All you would be out is the gaskets and getting your heads checked.
I have done the "replace the blown head gasket and hope thing" before on a 400. It ended up that the head was cracked, resulting in me hunting to find a new '71 400 with nonsmog heads for my truck.
Robert
So what I am reading is that you basically have two engines with (maybe) two good heads between them, right? I would pull the two heads I thought were good and get them checked out, then put them on the "built" engine and be done with it.
All you would be out is the gaskets and getting your heads checked.
I have done the "replace the blown head gasket and hope thing" before on a 400. It ended up that the head was cracked, resulting in me hunting to find a new '71 400 with nonsmog heads for my truck.
Robert
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FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
Bruno and I've taken our discussion off-line. But, I pulled the head that has the leak in the exhaust manifold bolt hole. And, saying it is a "leak" is a bit of an understatement as there is no back wall to that hole. The others are 1 3/16" deep, but this one goes back 3 1/2" before hitting what must be the curving top of the coolant passage.
And, I can't get enough light in there to get a picture, but I can say that the threads look good and I don't think they've been repaired. So, I think I'll have the head magnafluxed to see if it has cracks. But, if not may use sealant on the bolt and run it.
I have attached a picture of #3 piston. It says 451PF .060, so is obviously a 60 thou-over slug. But, is it the Sterling low compression piston mentioned on Bubba's site? That one is shown as a 451P. What does the "F" mean?
And, I can't get enough light in there to get a picture, but I can say that the threads look good and I don't think they've been repaired. So, I think I'll have the head magnafluxed to see if it has cracks. But, if not may use sealant on the bolt and run it.
I have attached a picture of #3 piston. It says 451PF .060, so is obviously a 60 thou-over slug. But, is it the Sterling low compression piston mentioned on Bubba's site? That one is shown as a 451P. What does the "F" mean?
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FTE Legend
Joined: Jul 2010
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From: Northeast, OK
I wondered that. The 451P is said to be cast, but..... Maybe someone that knows will chime in. The 451P is supposed to give only 7.9:1 CR. Did Rusty run like he had that low of compression?
Postmaster
Joined: Nov 2009
Posts: 4,575
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From: Broken Arrow , OK
I dont think so. That is pretty good compression for the 87 octane gas though. I wonder if thats why those pistons are recomended? Cars and trucks were running on lower octane in the late 70's and 80's. So maybe that was part of the formula that woke the 351M/400's up.
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