521 Heads - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

nourse · 02-24-2010, 18:11

A have factory c-9 heads on it now, would like to put scj heads on or p51 heads. I know you have to notch the intake valve for these heads with flattop pistons but I have the mahle 38cc inv dish piston, would I need to notch these pistons or would the head fit without mods to the piston?

Paul Kane · 02-24-2010, 21:54

Quote:

Originally Posted by nourse

A have factory c-9 heads on it now, would like to put scj heads on or p51 heads. I know you have to notch the intake valve for these heads with flattop pistons but I have the mahle 38cc inv dish piston, would I need to notch these pistons or would the head fit without mods to the piston?

The volume of the dish has nothing to do with it. The valve pocket for an SCJ head is in a different location on a piston crown than the valve pocket for a C9VE head. Whether or not there are clearance problems also has to do with valve timing events and other combination factors. It is more likely than not that you will need to notch the pistons, but we cannot determine this without more infomration, and frankly, without a mock up.

Paul

nourse · 02-25-2010, 06:27

Thank Paul. What is the best standard aluminum head with about 72cc? When I built the motor last year I didn't know the scj head need a differant piston, It's my own fault for not doing my homework!

Paul Kane · 03-04-2010, 18:45

Quote:

Originally Posted by nourse

Thank Paul. What is the best standard aluminum head with about 72cc? When I built the motor last year I didn't know the scj head need a differant piston, It's my own fault for not doing my homework!

Great street/strip heads for a lightly driven 521 might be the TFS Street/Strip heads, around 74cc chambers.

Paul