Carb size for 350 chev in a GQ

[demo2]

I have a 350 chev in my LWB GQ running duel fuel, its got a 750 vac sec on now and does a tad over 3kays per litre on lpg and less on petrol and thats around town driving without a lead foot. Has a cam of unknown origin but i know it has alot of overlam which dont help on the gas as they can never get proper co readings and 485 thou of valve lift. I will change the cam later this year but i was wondering if i put a 600 vac sec on would this get fuel economy? it only did 4 kays per litre with the old 4.2 so seams 1 kay per litre less for a 350 chev is about rite but a 750 should only go on something like a fast street car with heads and cam etc
What do you think?
cheers

[brad-chevlux]

changing the carb won't make any difference to the LPG

on petrol you may get slighty better but only if the carb is setup right with an oxygen sensor in the tail pipe.

just chucking any old carb on will more then likly be a backward step

[demo2]

ok cheers mate. Wont bother then