Smoking, sluggish, low compression engines usually have bad pistons and rings to blame for their anemic condition. Rebuild your engine properly with the finest parts available (original equip., kolbenschmidt or mahle). Do not accept imitation or aftermarket pistons. Do it once! Do it right! If you are looking for a little extra hp and torque with your rebuild, try a set of higher compression European specpistons and get performance and factory reliability.