Pictures tell the story:

2-1/2" JBA tips (too big)
1-7/8" stock GT tip (too small)





Cut off the tip at the 2-1/4" diameter point in the taper.  A piece of 2-1/4" pipe slipped over it makes this real easy.  Just mark where the pipe stops on the taper.



When you cut it, you will wind up with an inner and an outer section


Hammer the louvers in as far as you can.  This will allow room for the cutoff wheel to fit inside the tip.


Once the louver is flattened out, use a cutoff wheel to cut the ID of the tip to remove the louver.  Be careful, you are cutting thorough only the first layer of a double wall pipe!




Once the louver is removed, tack weld the two pieces of pipe back together


Clean up the welds, then weld a section of 2-1/4" tube to the tapered tip.  I have found that 2-1/2" is so big, the welds end up too far towards the big end of the tip and can show through the hole in the valance.  If you are using 2-1/2" pipes like on my 66, take the 2-1/4" tube to a muffler shop and have them expand the 2-1/4" tube so it fits over a 2-1/2" pipe.  That hides the welds behind the expanded part so you get a clean look.



Finished result.  You CAN weld these in place so you don't have to have a helper run along behind the car to hold them in position.  When installing these, get all the hangers in place and weld the tips last so you can get a perfect fit.

2-1/4" open through tip (just right!)


If you take the extra time to get everything squared up and equal height, your exhaust system will look alot better.