Good to know. I don't need CR numbers that high, but I'll basically be building the same motor as you. I say that I won't likely rev past 5k, but the current B18 in my 142 falls on its face at 4500, and sounds like it's going to explode at 5, so maybe that where my reticence comes from. If I build a motor that is still pulling at 5k, I'm likely to wring it out every so often.

Regarding carbs, I already spent the money to have my SU HS6's properly rebuilt (new throttle plate bushings, and all new brass parts), so I'm good to go there.

The flywheel felt ungodly heavy when I pulled it, so I'm also thinking about weight there. Any ideas how much it can lose without starting to feel like a honda civic in traffic?