I was told that you can take 2 750 Vac Sec. and make one 750 DP by taking the front bowl off of one and putting it on the back of the other one? Has anyone heard this, know if it will work, Have any advice to give on doing this.

The linkage won't work...how will you open the secondaries?

Front and rear bowls are different.

A typical diaphram secondary ( vacuume secondary ) Holley carb has no provisions for a secondary pump passage / discharge nozzle / check needle ect on the main body..... So even if you modified the external parts ie... linkage and bowls it still wouldnt work..
There is no place for the pump shot to go once it leaves the metering block .

Yeah, and I saw a wacko 3310 on E-bay a couple of days ago. Has a 1-1 gear drive adaption on the linkage to open the secondaries, and a 50cc pump. the shooters have two "normal" holes and two LONG_ASS extended nozzles that fit through holes drilled in the air horn and squirt into the secondary side.

Sounds like too much low-grade '60's LSD to me.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2450064784&category=33550

Those gear drive mechanisms are DEADLY !! One piece of grit or sand or other trash and it can stick...Not a good thing if it sticks wide open.... And your trying to stop the car....

That was indeed a 60's modification that was used mainly because of a lack of understanding on how a diaphram/vacuume secondary carb works.....

That carb pictured is all but useless the way it sits.

Get a 750 duel feed ...... works right out of the box, so I am told.. graemlins/hurray.gif