Speed Pro H825CP Specifications

[Muad'Dib]

Ring End Gap:

I was reading the Keith Black Catalog (Yeah i know these are Speed Pro Pistons) and it says that for a Hypereutectic, you should set the top ring gap to 40% larger than what the recommendation on the rings are... Does this sound accurate? From the reading i have done on Hypers, that seems about right.

Piston to Cylinder Wall Clearance or Total Finished Bore Size:

According to the card that came with my pistons, the Total Finished Bore size should be printed on the specifications label attached to the box. However, with the set of H825CP's i have, that number is not given. Does anyone know what the Piston to Cylinder wall clearance or Total Finished Bore size is suppose to be for these pistons? Preferrably for the .060 over's..


Thanks guys!

[Muad'Dib]

I called Federal Mogul today and this is what they had to say:

Ring End Gap:

I was reading the Keith Black Catalog (Yeah i know these are Speed Pro Pistons) and it says that for a Hypereutectic, you should set the top ring gap to 40% larger than what the recommendation on the rings are... Does this sound accurate? From the reading i have done on Hypers, that seems about right.

Use Ring / OEM Specification for top ring end gap. Keith Black hypers need the 40% gap increase because they move the top ring land closer to the top of the piston thus absorbing more of the heat. They said this is not done on their pistons.

Piston to Cylinder Wall Clearance or Total Finished Bore Size:

According to the card that came with my pistons, the Total Finished Bore size should be printed on the specifications label attached to the box. However, with the set of H825CP's i have, that number is not given. Does anyone know what the Piston to Cylinder wall clearance or Total Finished Bore size is suppose to be for these pistons? Preferrably for the .060 over's..

They said 3.935 to 3.9355 (3.935 1/2) Final Finished Bore Size. AKA .0005 to .001 Cylinder Wall Clearance


I also emailed them to see if i got a different answer, but the guy i talked to seemed to know his stuff.