Bohnzii Posted July 30, 2006 Share Posted July 30, 2006 Would someone out there please share their knowledge and experience with two four barrel carbs? My Z has a 400 sbc with two Edelbrock 600's on a vintage Weiand low rise dual plane manifold. When I started it for the first time the engine sounded good and water temp never went over 180. But after less than 5 minutes idling at 1000 rpm the #8 header pipe started to glow red. I shut it off and let it cool off. I unhooked all vacuum lines to the carbs and capped them off at the carbs thinking a vacuum leak maybe was causing a lean fuel problem. I started the engine a secomd time and the same thing happened with water temp never going over 180. I shut it off and the engined dieseled to a stop. The heads have the proper steam holes for the 400 block and fuel pressure is set at 6 psi while running. Is it something as simple as opening the idle circuit screws a little more? Does it sound like that rear carb is too lean or do I have other issues? Any ideas, suggestions or recomendations would be greatly appreciated--thanks Quote Link to comment Share on other sites More sharing options...
John Scott Posted July 30, 2006 Share Posted July 30, 2006 Late (retarded) timing can cause this as well. I think just one tube would indicate lean fuel distribution. Quote Link to comment Share on other sites More sharing options...
Bohnzii Posted July 30, 2006 Author Share Posted July 30, 2006 Thanks for the Idea/info. I had a friend call a few minutes ago with the same suggestion. I've been putting this car together for the last eight years and at the moment of truth--- I go brain dead. I've played with 3 deuces in years past but never 2 quads. Basically a carburator is just a controlled fuel leak right? Quote Link to comment Share on other sites More sharing options...
John Scott Posted July 31, 2006 Share Posted July 31, 2006 Thanks for the Idea/info. I had a friend call a few minutes ago with the same suggestion. I've been putting this car together for the last eight years and at the moment of truth--- I go brain dead. I've played with 3 deuces in years past but never 2 quads. Basically a carburator is just a controlled fuel leak right? A pretty sophisticated fuel leak, but yeah. After reading the ongoing gliches and bitches in the MS FI forum, I'll be carbureted for a while. I'm sure you've heard the preaching of single 4 bbl usually run stronger than mutiple carbs. Still, the sex appeal of retro dual quads is undeniable. Good luck on the issue. Quote Link to comment Share on other sites More sharing options...
2126 Posted August 10, 2006 Share Posted August 10, 2006 A possible contributing factor on the dual quads may be in how the throttle linkage is set-up. If under easy driving condition (not much fuel/air required), some of the old set-ups employed only the primaries of the front carb, causeing leaner mixtures to some cylinders. Others linkage set-ups employ both sets of primaries, netting a more even distribution. Of course under full throttle all eight venturis are working. I'm curious....I have no idea how your 400 sbc is built but, I was wondering if two 600 cfm carbs are too much for your engine to handle? Quote Link to comment Share on other sites More sharing options...
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