# GTO Head Swap



## revOlg1206 (Oct 31, 2009)

I have a 1967 GTO 400 4speed and when i was breaking down the engine i noticed that my heads might be beyond repair. I was wondering if anyone would know if 455 heads would bolt up to a 400 block.....i know someone that has a set and i was wondering if they would work before i purchased them..thanks..


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## 68greengoat (Sep 15, 2005)

Yes.....


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## geeteeohguy (Feb 2, 2008)

Yes. All '67 and up heads interchange except for the 301 v8. Here's the deal: the head number (casting number) is really important. You want a combustion chamber size you can live with, like 80-100cc. Example: a set of #66 heads off of a 1971 455 have 114cc chambers. On a 400 v8, this translates into about 7.25 to 1 compression ratio. A set of #64 heads off of a 1970 455 have 87cc chambers. This equals about 9.4 to 1 compression on a 400 engine. You can go to different websites like Wallace Racing and get a head chart that posts ID numbers and specs. Lots of combos out there...do the research. Good luck.


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## jetstang (Nov 5, 2008)

:agree Spend the time researching and finding a set of heads that are livable on pump gas without losing all the HP. Early heads don't have hardened seats, so that is an additional expense with pre-72 heads. 6X-4 heads are later model, have hardened seats and aren't that expensive.


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