Blue smoke at startup and at takeoff.

I just bought a 1988 silvy 5.7L for 800$ I knew about the blue smoke before I bought it but it is in good shape and 800$ is a deal. It smokes at startup and when a take off from a stop light. If I start it and rev it up in idle it dont smoke and after take off it dont smoke....its just like a poof of blue smoke at startup and takeoff. Blue smoke means that its burning oil right? whats causing this?

Usually it's valve seals. Rubber seals that go on the valve stems and/or on the valve guides. Keeps oil from seeping and being drawn down along the valve stems. Not a big job or expense to replace these. That is about the age for your truck for these to go bad I'd guess.

They're not that bad to do with the engine in the vehicle. Just get an air compressor and a fitting that will go into the spark plug threads. With the cylinder full of compresed air (make sure both valves are closed, or you could drop a valve into the cylinder), use the rocker arm style valve spring compressor (I got one for $8) to get the springs off. Replace the valve stem seals, replace the springs and rocker arms, and move on to the next cylinder.

If it smokes worse at initial startup than subsequent, it may just be the seals, if it smokes all all starts, you may have bad rings too.

mine smokes when i start it after it sits for over 30 minutes and also if u rev it up it smokes as it is revving back down. i hate that blue smoke lol. if it smokes when revving down like that is it probly my rings also cause i trained monkey could see that my valve seals are bad but i dunno about the rings yet

The acceleration of the truck is great, and it still has all kinds of power i dont think its the rings....Is there a detailed "How To" on how to replace the valve seals, maybe with pictures? thanks

I'd reccomend getting a repair manual for your truck. I have a Haynes manual ('68-'87), I just checked, and it has a VERY detailed step-by-step, along with a few pictures.

mine smokes when i start it after it sits for over 30 minutes and also if u rev it up it smokes as it is revving back down. i hate that blue smoke lol. if it smokes when revving down like that is it probly my rings also cause i trained monkey could see that my valve seals are bad but i dunno about the rings yet

Do a compression test and recored the results for each cylinder. They should be about 150 PSI for a V6 or V8, and about 130 PSI for a straight 6; the pressure in all cylinders should vary no more than 20%. Put a few squirts of oil (the heavier the better, 90 weight would work best)in the spark plug hole (use an oil gun, or a syringe. Make sure the oil is squirted in with enough force that it hits the cylinder wall.) and repeat the test. If the PSI rises more than a pound or two (the oil will not compress, therefore compressing the air slightly more), the rings are worn.