This 4500 spacer is machined from one piece 6061 aluminum and contains an SFI approved burst panel. The overall height of this spacer is 2.375" and is ideal for high horsepower boosted applications. Not only will this panel help with improved air distribution between cylinders, it will also act as a much needed safety device. Engines that are making a lot of horsepower need a lot of fuel. With all that fuel, if you have an event that the fuel can't make it into the cylinder (broken rocker arm as an example) the fuel then ponds in the intake manifold and can cause a backfire. Enough fuel can cause a pretty big exploding. The burst panel is designed to blow out and release this pressure before it has a chance to damage other important items. Add an insurance policy to your build with a burst panel spacer.