Blue smoke when starting up?

[Asahi123]

I have a 72 chevy and have checked the compression and check the pcv valve all good. But when I start my truck and get going i can see blue smoke coming out the back. The plugs look good. Is it the valve seels need to be replaced? Or should just have a valve job done on the heads. It does seam to use oil and I have stopped all of the oil leaking. Thanks for your help.

[cableguy0]

Blue smoke only on startup generally indicates bad valve seals. Good compression numbers pretty much verify that its valve seals and not rings. It is also possible that the valve guides are worn but Im not a fan of putting rebuilt or new heads on an old engine. If it was me I would just yank the valve covers and pull the rockers,use compressed air to hold the valves up and pull the springs to change the seals. Its a bit of a PITA to do in the truck but with the proper valve spring compressor its not that bad.