There is an exhaust manifold sold on the aftermarket called a Powerlog. It reportedly flows much better than the stock rear exhaust manifold so I tried to install one on my series II engine The problem is that the "powerlog" locates extremely close to the A/C compressor. There was like less than 1/4" clearance there. I decided not to use it because high temperatures so close may slightly impede compressor efficiency but more concerning is the shortening of the compressor life. I sure wish that someone would make a shorty high efficiency header or manifold that clears the compressor like the stock unit. Comments?