hi! So my 66 slant is burning oil bad! I’ve replaced the valve stem seals and the guides didn’t feel bad? With my calibrated hand wiggle I mean. It has a lot of oomph tho? I can hit the gas and she’s moves but also leaves a dark cloud. Could it be the valve stems? Or the piston rings? I’m thinking why does it run so well if the rings are bad? Thanks in advance!