Mattback knows this stuff. So does Enthalpy, but he doesn't post ever. Where's Martin? Those guys probably have the most experience locally. All of them will tell you that in our applications the CPs and Wisecos are both good choices.

For the record, CP recommends .0035" wall clearance. Wiseco recommends .0025" clearance. CP tolerances are super consistent. Even their ring packs; if you bore to .0035 clearance, the rings will come out dead nuts on for the recommended gap. My Wiseco's had a little bit of a variation, I think it was .001 to .0015" overall. It shouldn't matter because you should be match boring your block anyways.

And I don't get where 4g-bs-tard gets off saying what companies do their own R&D. Lets sumaraize his analysis: All US companys suck and don't do testing. All Japanese companies rock and do extensive R&D. That just seems like a longwinded way of saying OMG JDM. The truth of the matter is that a lot of Japanese companies contract internals out to US/Euro companies. For instance, it's a public fact that JUN pistons are made by Cosworth. In the end all pistons do is sit behind combustion at xxx temp and xxx pressure and push on a rod/wrist pin. If your engineering department is so bad at deisgning pistons that you need to do exhaustive in house testing for every single piston diameter/dish then you have no business selling them in the first place. Man, if only there were some sort of software that would allow me to run simulations and FEA... I mean, SR pistons can't be anything like ECOtec pistons, or K-series piston, or any other piston on earth... /sarcasm. As many pistons as Wiseco and CP sell each year for SR and KA, and how well they work, it'd be rediculous to assume that they've never seen them in operation at their own facility. Grow up!