Natural finish. The basic S motor, designed as stock replacement for a stock Evolution Big Twin, instead of overhauling it. Engine is stock 3-1/2\" bore x stock 4-1/4\" stroke giving stock 80\" (1340cc) displacement. Cast pistons with a 8.4:1 CR and a 508 cam. Stock like performance with stock like life. Note: Sold as \'Long Block\'. Carburetor, manifold, ignition and charging system is not included.