The history is that 2 years ago I put a short block in this unit. Recently I discovered it had a leak on one head gasket. This unit is propane so I pulled everything off and replaced the head gasket. Took it out for a run and after about 4 minutes it was blowing smoke out of the muffler big time. It was also leaking oil out of the top of the valve cover due to the fact I damaged the breather seal when I put it back. Fixed that but again after about 4 minutes big time smoke. Got a gage to measure vac at dipstick and it is -10 initially then about -5 when it is blowing smoke. Oh before I put on headgasket it was not using oil or doing any smoking. Pooh hoo another rockie error.