Slant 6 Vibration

I agree with Pishta's post 40. Im guessing the Pssst sound from #2 when doing the compression test was a leaking exhaust valve. Personally I'd keep the same head and have it rebuilt. Maybe pull #2 piston and check it and the rings, dingle ball it and run it. Make sure you check the small 1/8" diameter oil feed holes in the rocker shaft for pluggage. Mine were all clogged but it hadn't been run for 31 yrs.

My personal experience is with my 64 225. From the outside it looks normal but when I COMPLETELY rebuilt it I couldn't just put it back together stock so...I had the head rebuilt with hardened seats and milled .080. Charlie S says that's the #1 upgrade with no negatives. I also spent about 10 hrs gasket matching and pocket porting. I had the cam reground by Oregon cams for about $100 invluding shipping, stock lift was .375 and now i have (IIRC) .420 and 252* duration. I hogged out the short turn radius in the stock intake under the carb and opened the bore to match the carb gasket. Also increased the exhaust pipe diameter. Looks stock but really runs well.