Iv been reading David Vizard's book on modifying A-series engines and they have an integrated manifold like the L head. He determines this is a bad thing for making power. The heat it makes goes past the point of being beneficial causing much too much gas expansion in the intake. Also makes it makes it much more susceptable to detonation which isnt a problem that iv had but the fact remains. So I thought it would be a good project to make my own intake. I settled on building the intake rather than the exhaust because it was easier, still provides access to the valve cover, and less likely to leak. The tubing is the same size as the original but the hot spot is now removed and it works as it should. I think it will help alot on hot days climbing hills especially the engine seems to loose power when being worked hard.