Well after finishing up two 562s on Saturday I was a little bored last night and decided to do some more experimenting. I had a 372 top end laying around that I had previously done some work on and decided to pair it with a slab sided 268 piston. The top end has a widened intake, widened & polished exhaust, lower transfer wall lowered, little material taken out of the lower transfers, and stretched uppers towards the intake.
I took 040 off the squish band instead of doing a pop up which resulted in a 020 squish. 372s have a little lip on the squish band which must be about .005 because normally with 040 pop up 268 you get around 025 squish but once I smoothed the whole band up it ended up at 020. I then took .002 off the base just to clean off all the crap stuck to it. Easier to let the lathe do the work compared to me scraping it off.
Here's the numbers I decided on. 100, 122, 84. (268 piston will give you a 83-84 intake without doing any grinding).
The ring still needs to seat so as of now compression feels stock. Case compression felt very strong, saw ran great. I think I could take the exhaust up another degree to 99 and see some gains. Saw spins up pretty squick, held rpms very well.
Conclusion? I couldn't tell a difference between doing a band cut or pop up. Other than when cutting the band you'll have more grinding to do. The slab sided piston felt like it had more case compression, still felt light but maybe a touch heavier than the windowed piston.
I sharpened the chain pretty aggressive, used the soft setting on my husky raker gauge. Saw seemed to pull it just fine.