Having a bit of a problem with oil burning. Put a 408 stroker kit on a 351C engine. Ever since installation of kit it has been burning oil. Ring gaps were staggered during install. Valve stem seals have been replaced Guides looked good and the heads were done about 2 years before the engine. It has 1200 miles on it. Have good compression on all cylinders. Sometimes it blows blue smoke sometimes it doesn't. Have dual exhaust and the right side blows more than the left. There is oil in the right tailpipe. Some of the smoke I'm sure is due to the rings still being bedded. It seems to blow smoke when it gets hot. It is not running excessively hot though it does run on the upper end of the opperating temp, but this is nothing new, it has always done that. I got it hot enough to blow smoke last night and did a compression test with it still hot. The compression was signifacantly less (around 150 psi) normally 175 - 185. Started with the right side and as it move to the left side the engine had cooled some and got excellent compression. Did the right side one more time and since it had cooled it returned to normal. All cylinders are 175-185 psi within 6 cranks of the engine. I suspect that it is due to the difference in heat expansion between the cast iron block and the forged pistons. My question Is this caused by bad machining. It was done by a reputable shop, they had the whole kit including pistons and rings, and the pistons fit like a glove when I got it back. It seemed like pretty solid work with good machining. I am working on making the car run cooler, but I was wondering if anyone has experience with this type of problem and what can be done about it.