Ok, carb is a Holley 600 cfm, with vacuum secondaries. The scondaries have always opened really late [too late to help me out @ least]. Is there anything I can do to make the secondaries open sooner instead of installing a different spring?

 

nope..just install a lighter spring.

 

Hi,
I have an '86 Transam with pretty much the same setup. Yes, I know what you mean as I also found it hard to get the secondarys working when I wanted. I experemented extensively and settled on the second weakest secondary spring available (Think it was the clear or no-colour)! I also used a green accelerator pump cam, larger shooters with directional nozzles(From a 350 2bbl I had) and a 2 stage power valve.
This is what I have settled for and am more than happy... Good acceleration and yet is surprisingly economical as well. During the tuning stage I connected a Digital Volt Meter to the, now, un-used o2 sensor so readings can be done 'on the move'. I've since disconnected the setup as it's no longer required.
Hope this has been of some use... Regards...

 

Woops!!!
Correction... It was a yellow secondary spring ... Sorry, was quite a time ago! Regards...

 

Check to see if the vacuum ports in the top if the venturiis
are open. This is where the vacuum pot picks up its signal.
Do not enlarge the holes. They are big enough. Check the condition of the gasket that seals the vacuum pot to the side of the carb. You shouldn't be able to feel the secondaries open
it should be a smooth progressive opening. The secondaries will
only open enough to feed the motor what it wants. A near stock
350 won't make the secondaries open all the way.