There are a few Holley 650s to choose from (with mechanical secondaries)
0-4777C
chromate dip finish / mech choke
http://www.holley.com/HiOctn/ProdLin...C/0-4777C.html
0-4777S
shiny / mech choke
http://www.holley.com/HiOctn/ProdLin...C/0-4777S.html
0-80777
choke / braided fuel line
http://www.holley.com/HiOctn/ProdLin...C/0-80777.html
0-80542-1
race ready out of the box / 30cc
http://www.holley.com/HiOctn/ProdLin...0-80542-1.html
0-80541-1
race ready out of the box / 50cc
http://www.holley.com/HiOctn/ProdLin...0-80541-1.html
Personally I like the race ready units and think the 30cc unit would be sweet
0-80542-1
The race ready units are really well made but they come at a premium price. This unit sells for $589 at RACESEARCH.COM and $582 at Jegs.com
http://www.racesearch.com/CGI/racese...iption_id=1685
If you decide to go 750, you might consider
http://www.holley.com/HiOctn/ProdLin...0-80528-1.html
hope this info is useful
Andy
http://www.cobralads.com