I did the valve gaps yesterday (first time since I bought it!).

The gaps were all too loose (anywhere from .008 to .014). I set them all to .006

Would the loose valves have mattered? What effect would it have had?

It will affect running as the valves are open for a shorter time.
Don't know if it would do much damage even though it's not good, it can cause excessive hammer on the valves, so you might see some peening over of the adjustment screws.
I'd be watching them closely though and see the gap you set is stable or it may be showing some problem in the motor.

OK thanks I'll keep an eye on them.

Gotta get me some new cover gaskets anyway so I can re-check when I replace the gaskets.

I bet it ran better after

kkk