Serious Q: Re: Carbs., Running moderate cammed 350 SBC Options

[Dr. Roger]

Got two vac secondary carbs (600 cfm smog carb and a 750) which I now know are in need of rebuilds.

The 600 runs but, on this heavily cammed engine, like *hit. Idle circuit has very little adjustability. And it's got more vacuum ports than I can count.
The 750 is a bit too much I think for the 350.

I've run 650 double pumpers with great success and am thinking about installing a 650 spreadbore. Small primaries/large secondaries.

Goal here is to keep higher velocities off idle for responsiveness and, due to engine displacement, not over carb it like if I used the 750cfm. 6K redline...

I'm about ready to go the the local parts place and plunk down some spare change on a new 650.

WWYD? =-))

Roger

Pic is the 600 smog carb....... Come hear it run.... Swap ya' for that old 650 dbl pumper..... =-)))

[messix]

throw and rebuild kit on the 750 holley. that 600 emisions carb is junk. the 750 will work good, the bigger carb helps if your not running a carb spacer because the slower air fuel mix turns into the runners with out slamming in to the intake floor first. [what intake are you using?] i had this problem with a 400 hp 350 once, it idled like crap and just wouldn't get off the line well. i couldn't use a carb spacer to smooth the flow in to the runners because of hood clearance and tried the bigger carb and that did the trick.
get a holley build book that shows how to adjust and rebuild these that will help you tune it. shouldn't take much, pay attention to the float level and fuel pressure, holleys are picky with that, oh and they go hand in hand; rais the pressure and the fuel level goes up and your mixture gets richer. use a fuel pressure regulator also and run at 4psi this gives good float stability.

holley carb arent that bad, i run one on my jeep off road it passes emissons and runs steady on very steep hillclimbs and even runs with the jeep laying on its side. i have done alot of easy work on this to get it there and now they come out with the're truck avenger carb that has all the mods that i did to mine.

good luck post any problems or pm me and i'll help you get thru them.