The carb could be a double feed w/vac seconds but not a puddle dumper which would have mech seconds. Mechanical seconds are great for racing and using copious amounts of fuel. Vac seconds are more streetable. Many if not most street carbs come with vac seconds.custom762007-03-18 18:34:38

Puddle dumper (aka double pumper)

I've never seen a DP with vacuum secondaries.  Maybe you are confusing the two fuel bowls with a DP?  My 600 Vac sec will open on the driveway if I goose it for a short amount of time.  They won't open all the way, just enough to know my carb is working correctly.  When out on the road you should be able to feel and hear them open.

Thanks for all of your input, especially stuff regarding correct nomenclature (double-pump, double-feed...........who knew?/). Anyway, I will be holding the throttle open a little longer when I test in the driveway; we'll see what happens. I can't really tell when I'm driving because the sidepipes drown-out any sucking noises coming from the engine!!

     You can buy assorted springs for the vacuum secondary that will allow the secondary to open at different rpms.  The standard spring that comes in most Holley vac. sec. begins to open around 2240 rpms, pending engine configuration.  The Holley spring kit comes with directions and recommendations.

Thanks Steve (smscorvette)! Sounds like I need to get a comprehensive Holley carburetor book, and start fiddlin'.

hubby just got a new holley and came with a very good dvd. cant copy it(i tried)see if you can get hold of it,very good on tuning info.

Fiddin' is correct.  Make one change and take her down the road.  Follow Holley's suggestions and you will find some extra HP.  If you can find a shop that has a drive-on dyno, sometimes they will let you rent it just for making carb adjustments.  Good luck!  The Holley carb book is not a bad investment. 

Steve has a good idea about the Dyno Jet, if you have a good local tuner with a chassis dyno you can dial in the jetting, secondary springs, distributor curve, and timing for maybe the price of a new carb, then you'll know what you really got.

     Bob- I have just the guy for you....Bob Jennings Dyno Tuning. He's up here in the Valley. Been around for 40 years. I've known him and his family since I was in high school and the work is top notch. He has been featured many times in Hot Rod, Car Craft, etc. Only problem is he's not open on weekends......Let me know. I can set it up......He can get you dialed right in.....