Hey Jimmy . . . see Chopper Dave's Casting Company for one of these . . . I like 'em better than the S&S ones . . . and you'll be Loud AND Fast AND Rule too ! NOTE: I've heard they work best if you overlap the velocity stack lip by about 1/4"-3/8" of an inch. Not in too far, not out even with the lip.
I got it runnin' pretty decent in these cool temps. Starts better. I bundled up with leathers, insulated denim pants and a Bell Vortec and put on a few back-road miles. Bar to Bar.
This is the best working old, steel leg Sporty frontend I have . . . It never tops out, bottoms out, or wiggles at high speed. This bike has the original frame, forks, shocks (and engine) so that might be the difference? or at least help . . .
Long reach plugs. My horn bracket broke - so I fixed it. Now it's good for another 25 years since I made the last one . . . Have a Great Day !