The B1 BS was designed as a replacement for the iron Mopar head. The standard intake valve is 2.200 and the standard exhaust valve is 1.810. The B1 BS is absolutely the best buy for Mopar racers that would like to add horsepower with minimum changes. The only changes necessary are rocker arms, head stud kit, and longer pushrods. The standard parts that may be used include: headers, intake manifold, closed chamber or flat top pistons, and valve covers.