Hey, 93 GMC Suburban 350 5.7, 160k original, light white smoke on startup, heavy on accleration, no overheating, no oil in water, no water in oil, compression within range, no missing, does not seem to change or go away after normal operting temp. smoke does not appear to have blue tint and does not smell like coolant however it appears to have moisture within. Sound like Valve guides or head gasket(s)? Does synthectic oil burn like crude oil (smoke or no smoke) for diagnostic purposes? High percentage of mass oil leaks if synthetic swithed temporarily? Currently regular 20w50 is sitting in the pan. Thought it may have been intake gaskets, leaking into a port, swithed um out no luck same thing still goin on.

 

Most likely going to be valve seals. Very common for chevy engines. They use very small o-rings around the valve stem to keep oil from seeping into the combustion chamber. Usually that puff of grey smoke comes from a small amount of oil running down the stem past the guide while the motors sets overnight. You can change these out in a day easily. Go to the dealership and get a set of umbrella style seals. You can also go by a local machine shop and pick up a set of teflons seals for the same price as the dealership units. Then you can get the valve spring compressor tool and spark plug ports fittings to change them out. You will need to run the valve after to get the rocker arm adjustment set. Go to www.camhelp.com for proper procedure. Hope this helps.