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FE Power Forums => FE Technical Forum => Topic started by: AlanCasida on February 25, 2022, 02:24:41 PM

Title: Increasing combustion chamber
Post by: AlanCasida on February 25, 2022, 02:24:41 PM

I have been entertaining putting my 428CJ motor in my '67 F250 for towing but I would like to lower the compression so I can run regular gas. When I had the machine work done on the motor we found that one head had been machined to 68cc so my machine shop milled the other head to match. Then to lower the compression they machined a 22cc dish in my pistons. That yielded a static compression of around 9.75. I would like to get it closer to 9.0. My question is would it cause problems and/or would it be feasible to open the combustion chamber up to around 75cc.   

Title: Re: Increasing combustion chamber
Post by: blykins on February 25, 2022, 02:41:25 PM

The quick answer is yes, there are guys with CNC programs who can open the chambers up.

The longer answer is with the right camshaft, it would be easy to make a towing application work with 9.7:1.  I have towing engines out there with that kind of compression.

Title: Re: Increasing combustion chamber
Post by: AlanCasida on February 25, 2022, 02:58:51 PM

Quote from: blykins on February 25, 2022, 02:41:25 PM

The quick answer is yes, there are guys with CNC programs who can open the chambers up.

The longer answer is with the right camshaft, it would be easy to make a towing application work with 9.7:1.  I have towing engines out there with that kind of compression.

Thanks Brent.
The cam that is currently in it is an older Comp dual energy cam #33-208-3  275 DEH. .515 int/541 exh lift   219 int /232 exh dur@.050 110 deg lobe sep.

Title: Re: Increasing combustion chamber
Post by: JC-427Stroker on March 06, 2022, 12:50:34 PM

How much can you get the compression down with a thicker head gasket ?