I have a used Z28 1987 with 71,000 miles. It runs very well. The people I bought it off of only put 6000 miles on it the last 10 years. It runs well and is very strong. However, on startup I get a puff of smoke.

Not every time - the smoke is blue. Engine is not using any oil that I can tell and the gas mileage hasn't been horrible.

Thoughts? Should I be worried?

 

blue smoke is a sign of burning oil

 

smoke at startup only is usually valve guides or seals. check intake gasket to. mine was so lose the oil was leaking in the intake and getting sucked into the cylinder.

 

If you only have the smoke on start up after the car set for period of time, I agree it is the valve seal guides leaking (small amounts) oil into the cylinders (not all of them). It is a common problem with SBC engines and you can ignore it until the leaks start affecting oil useage, then it will require replacement of the seals.

 

yes, valve guide seals. just about every sbc and its variants have that issue. its nothing to be worried about

 

Yup,not too hard to replace them should you want to.