I just got back from my Engine Builder and 5 beers and 1-1/2 hours later it turns out that the Holley 770 Street Avenger I have wont cut the mustard on a 469 c.i. Vacuum Secondaries = junk. Electric Choke = junk. Ajustibility for my engine = junk.

So, here I am dumping another 500.00 into my car and after a little homework I have decided on the B.G. Mighty Demon 850. My only question is....

What is the diffrence between Down Leg Boosters:
Down Leg (http://store.summitracing.com/partdetail.asp?part=GPT%2D5563010GC&view=2047&media=2)

And Annular Discharge Boosters:
Annular Discharge (http://store.summitracing.com/partdetail.asp?part=GPT%2D5563020GC&view=2047&media=2)