I have 9.7:1 CR and I have a hydraulic roller that's similar specs to an XE274 but with a roller has faster ramp rates, but slightly less lift. I have 3.23's and a 4-speed and it's far from lazy.
With low compression...go a little bit smaller. The XE256 just doesn't seem different enough from a stock 340 cam to me. AT LEAST XE262 IMO
