Would anyone know what the stock timing is on HF predator 8hp engines (hemi head). Can't find it anywhere online. Would it be the same as a gx270? 20degrees? The cam I'm running is a 275 which needs 28 degrees timing. The 6627 flywheel has no timing advance. I just want to make sure I'm running correct timing and don't have the equipment or know how to check it myself with a degree wheel. I read on nr racing site to run a 4 degree key, I see where some use a 6. Not sure if i need it at all.