Piston size ? (.20 over)

[Reloaded]

I've got a '99 Cobra block that's been bored .20 over. The machine shop is waiting to get some pistons from me to re-assemble the block. I'm just putting some stock '99 Cobra pistons back in it, but the Ford catalog doesn't list sizing like that. Here are my three choices for pistons:

Grade #1 (90.167/90.182 bore diameter)

Grade #2 (91.180/90.195 bore diameter)

Grade #3 (90.193/90.208 bore diameter)

Any idea which of those I should order for this block?

 

[Quadcammer]

uh, I hate to be a d-bag here, but you can't take a stock 3.55 piston and put it in a 3.57 cylinder.

all of the pistons you list (ps the measurements are in millimeters) have no chance of fitting in there.

so you will need an aftermarket 3.57" piston.

 

[Reloaded]

D-bag? How so? haha. I'm looking for info because I really don't know much of anything about this sort of stuff. So you're saying that those sizes listed won't fit the .20 over bore?

Can you suggest a cheap aftermarket piston that will work?

 

[Quadcammer]

right, so all of the sizes you listed all fit in a stock 3.55 bore. The factory simply doesn't have the time to get each cylinder exactly the same, so they use three different sizes of piston (grade 1 through 3) in order to get piston to wall clearance roughly the same on all holes. So all of these grades skirt around 3.55".

as for cheap pistons, I would look at probe, mahle, srp, modmax, and possibly TRW or something.

 

[Reloaded]

Ah ok. Great, thank you very much for the info. Much appreciated!

 

[Nazman]

Just to add to Quad's comments...you also need the exact measurements from the bores in order to get the right pistons. The the right PTWC could be achieved.

If you dont do your home work...then you may end up with piston slap or too tight of clerance (bad).

Its not just a matter of .020 over....there is more that meets the eye.

Naz