Richer then rich

[69cortezsilver]

well my simple cylinder head swap has become a nightmare! Have a 350 sbc .60over, decent size hydraulic cam,airgap intake,holley 650dp,roller rockers,headers,and swapped the old camelhump 194 valves, for some sportsman 2 heads. put engine back together and its running extremely rich, its popping thru carb, and surging etc...tried air/idle adjustment and nothing...is it true after 1992 holley carbs do not blow powervalves? i guess i can rebuild the carb and see what happens, just dont know how a simple head swap has created so much of a mess, it ran good before and i did not touch the carb

[TheJDMan]

Are you sure the distributor is installed correctly and the plug wires are in the right order? It sounds like it may be a tooth off or a pair of wires are crossed.

[69cortezsilver]

distributor is very close, and wires are correct....time to rebuild the carb im thinking

[sam 74]

Check for vac leaks also.

[Widetrax]

Chevys also have an electrical bleed through problem between the #3 & #7 plug wires. They need to be separated or insulted from each other.

[Rod]

back fire thru the Carb is the Dizzy, back fire thru the exhaust is the Carb, look for Vacuum leaks first, no leak then fix the dizzy

that's the quick shop diagnoses

[Derek@ModernSpeed]

If your positive it's not distributor/wiring related, move to checking for a vacuum leak. Are the valves adjusted properly? When an engine pops back through the carb it typically indicates a lean condition. Even though the carbs built post 1992 have pv blow out protection, the diaphragm can rupture. So, check valves, vacuum leaks, and then work on the carb. When a pv is bad it will typically load the engine up with fuel. That doesn't sound like the case here. Set your idle mix needles back to 1.5 turns out if it is only a 2 circuit idle system. Readjust for peak vacuum. If it's still popping your carb may be full of trash or varnish.

[69cortezsilver]

thanks for your responses guys, i backed out idle mix needles 1.5 turns, checked for vacuum leaks around intake, found none, took it for a cruise, its surging really bad, and when i jump on it it has hesitation/popping coming from either carb/exhaust or both, and is blowing a ton of fuel thru exhaust, the carb sat in garage for 8 months while i waited to purchase new heads, wonder if its just super gummed up from the old fuel that sat in it? i ordered up a rebuild kit, and if that does not work, i guess ill take to a professional and go from there

[69cortezsilver]

i have checked valves 4 times, pretty sure they are not the problem but?

[Derek@ModernSpeed]

Sounds like you should just go through it at this point. Let us know what becomes of it