Mr. P Body, What do you use to measure back pressure? I would love to learn this.
Very simple.. a inch of vac gauge( its inches of merc,HG).. drill it into the exhaust.. I just use a tap thats 1/8 pipe ad that way I can screw is a 1/8" pipe fitting.. once your done I just usually weld it close.. unless I need more readings.. very simple.. I did a few hundred of these at work