The Ford Barn

rotorwrench · 04-01-2021, 08:31 PM

Pickups didn't come with the 255 even if its a Mercury pickup. I have one 1CM head on one of my 51 Mercury cars but the other one has 8CM heads on both sides. The stroke length & piston pin location is the only difference between a basic Ford 239 and a basic Mercury 255. The Mercury 1CM head may compare to an 8RT truck engine head as far as compression ratio is concerned.

51504bat · 04-01-2021, 09:53 PM

Pretty much the same response here as over on the HAMB. Only way to know for sure is to pull a head and measure the stroke.

04-01-2021, 08:31 PM	#1
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 17,410	Re: 1cm Pickups didn't come with the 255 even if its a Mercury pickup. I have one 1CM head on one of my 51 Mercury cars but the other one has 8CM heads on both sides. The stroke length & piston pin location is the only difference between a basic Ford 239 and a basic Mercury 255. The Mercury 1CM head may compare to an 8RT truck engine head as far as compression ratio is concerned.

04-01-2021, 09:53 PM	#2
51504bat Senior Member Join Date: Sep 2013 Location: SoCal-Redlands Posts: 3,413	Re: 1cm Pretty much the same response here as over on the HAMB. Only way to know for sure is to pull a head and measure the stroke. __________________ Making the simple complicated for over 30 years.