At the optimum height and yielding the best overall gains, the Motordyne 5/16″ plenum spacer outperforms the competition and conveniently keep your engine cover and strut bar in place. This stealth modification adds 11HP-13HP and is the simplest to install. All Motordyne melt proof plenum spacers come with pre-attached, high quality gasket

(Due to Carb regulations this item is not sold/shipped to CA.- No International shipping)