We have the same stroke your looking to build, have run it for years with no issues. We just need a bit more power so, bit more bore size, new cam, Dwayne doing some head work and we should get what we need. You wont have any piston speed issues to worry about , we have turned this one 7200 many times with no issues.
Bearings we just took out after 3 years still look new and crank journals look like mirrors , rod bearings all looked good as well. I wouldn't worry about piston speed on your build.
Not to hijack, so I'll be brief. I'm assuming the quoted is referring to the 541 bore/stroke 4.50/4.25 combo. If so, that's a great report. I was curious why the OP was choosing that displacement.
As far as a factory block w/a girdle, I believe the BCR cap and girdle system is the best design, and was going to use that, BUT I figured why push towards the limit of a factory block, especially since I'm probably only going to get ONE shot at building a stroker. With the BMP block and my modest power expectations, I don't think I will ever worry about the block, or anything else breaking from being too close to its performance limits, and that peace of mind is invaluable at this point.
