Re: 9.2:1 CR in 327?

Posted by Anthony Pallett On 2012/6/27 18:21:29

Flat head engines in general are fairly sensitive to compression but 9.2 is not too high by any means, I would keep your timing fairly mild (stock specs) and put in a higher octane gas but I wouldn't think you should have any detonation issues. Just wondering did you mill the block any? this would also raise your compression ratio. The thing to remember is back when these engines were new the octane rating of gas was around 60 something but if you look at a page from the Ford V8 book you'll find that its very easy to run 9.2:1 with modern tech. the problem with VERY high compression on a flat head over an over head valve engine is you need to get the flame front out over the piston to get a good complete burn, a .020 cut on a head is not really much in refrence to the age of the engine and with inline motors tendency to warp heads. If your really loosing sleep about it there are custom gasket manufacturers out there that could make you a head gasket to take up the difference.