351c 4v heads?

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Nov 9, 2014 | 10:24 PM

#31

baddad457

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From: south louisiana

Quote:

Originally Posted by 72fordgts

If you pull it apart, please post the pictures of the pistons. 1971 400's supposedly have flat top pistons which give it a 9:1 compression ratio, but I have never actually seen any.

Even if they did, the deck clearance (down the hole at TDC) would still have been about -.120 Do the math. True zero deck flat tops would yield a 10.5 to 1 ratio in a 400 with open chambered heads.

Nov 9, 2014 | 11:32 PM

#32

BuzzLOL

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From: Toledo, Ohio

. Depends on the gasket thickness and cc's of the valve relief... I think the 1971 deck was supposed to be about .067"... using that and a steel shim (.025") head gasket (don't know what they used) I get about low 9's... assuming 5cc valve relief (may be more)... later engines add a dish to the piston, as well...

.

Nov 10, 2014 | 07:38 AM

#33

Gary Lewis

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From: Northeast, OK

I'm using Tim's flat top pistons zero-decked with a .039" gasket and expect 10.5:1 - according to Tim.

Nov 10, 2014 | 09:34 AM

#34

husker

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From: Manhattan, KS

The engine had been overhauled before I got it. I think it had fourty over pistons that were dished. The heads are off. I'll try to get a picture tonight.

Nov 10, 2014 | 12:16 PM

#35

baddad457

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From: south louisiana

Quote:

Originally Posted by BuzzLOL

I get 9.25 to 1 with those figures.

Nov 11, 2014 | 01:50 PM

#36

72fordgts

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From: Ontario, Canada

Quote:

Originally Posted by BuzzLOL

. Also, the same style pistons are no longer available in oversizes for rebuilding, so still need TMI pistons... and the pre-'78 blocks tend to crack... so the '71 heads would be the only desirable parts... along with re-usable crank and rods and miscellaneous parts...

I know the OEM pistons would be junk, but I just wanted to see if the 1971 400 has flat tops like many people say. I have never actually seen a 1971 400 with flat top OEM pistons and there are no pics I have seen on the internet, so I was just curious if it's true or not.

Nov 11, 2014 | 03:54 PM

#37

BuzzLOL

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From: Toledo, Ohio

. Haven't seen any disputes about the '71's having flat top pistons... everyone seems to agree on that... the '71 Ford 400 seems to be patterned after the '70 Chevy SBC 400 with both engines having nearly identical HP, torque, carb. size, and compression ratio spec.s... and both going to pot afterwards in later years... except Chevy started offering 4 bbl. carb.s later apparently for MPG and emissions reasons... (and maybe advertising reasons)

Nov 11, 2014 | 06:33 PM

#38

husker

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From: Manhattan, KS

The one engine I have is a D1AE. It was overhauled and has dished pistons in in now. It was overhauled before I got it. I'll try to get pictures up. My first attempt was a fail.