Does anyone know how big of a hold and best location to drill the baffles of my EG pipes? I've heard of guys doing it but not sure where or how big...

 

I drilled out the primary, (center) baffle on the SE mufflers I put on my 01 Heritage. Actually, beat them into submission is more acurate. The center baffle, on the SE's, was a plug stamped out of the surrounding baffle material, then bent into position as a blocking plate. It was the only thing blocking the straight through line of the pipe. I used a sledge and a half inch steel rod to bend it back toward the original material.
Check your pipes. It may be easier to push it out as opposed to drill it. If it is a flat plug, like most of the stock mufflers, use a long, 6 to 8 inch, bit. Start with 1/4 inch and work up to 1/2 inch. That should do it. Be prepared for the pipes to be loud. BTW, the older model SE pipes used to be straight through with just the metal baffle and no packing material.

 

Yea, I actually just did it, I put a small hole in the plug, then went bigger until it was pretty much all folded back. Hopefully this should do the trick!!!

 

Worked well for me. I always got compliments on the sound and the dyno said it worked well. It was a big bore 95 inch with SE cams. 93hp and 98ft lbs torque