Pan Evacuation question

[Mr. Fix It]

Just got a set of Doug's headers for my race car. Before I install them, I need to install a evacuation pipe in the collector. I hate to drill a hole or weld on the headers as they are coated. Will the evacuation pipe still work if I install it on the reducer? I plan to have it swedged to the 3.5 diameter of the collector if the evacuation effect would still work that far back from the tubes. Also, has anyone run a race type muffler with a pan evacuation system installed?

 

[Smiley]

I had mine originally setup with the tubes in the turnouts after the muffler. You will lose some efficiency, but if you install before the muffler, any back pressure will push back into the pan.

I changed to an inexpensive option using a vacuum pump from a old chevy convertible top and a puke tank. You can get some vacuum in the pan if you block it off, or use a breather on the opposite valve cover if your engine is not setup for a vacuum pump.

Here's a pic of the setup.