429 tunning problems
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429 tunning problems
So here is my setup, 429 bored .030 over, zero decked with stock 1973 style dished pistons, pocket ported dove-c heads with 2.19 intake and 1.76 exhuast valves, x4256h cam,striaght up timing set, 1.7 to one ratio crane blue racer rocker arms and custom made pushrods. Ignition timing right now is set at 15 btdc initial 39 degrees total with 10 degrees of vacuum advance, carburetor is an edelbrock 1411 750cfm. my problem is mid throttle bog, doest matter which jets, rods or springs i use i get the same issue in varying degrees, could this be a problem with my build or with the carb?
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From: BC Cana'duh
What are the cam specs?Lift,duration @ .050.What intake manifolld?Got headers?Sounds like carb though.Holleys are much easier to set up for a performance application.I don't know much about Eddy carbs,but I know they work better on stock style builds.I know that jets(on a Holley)won't contribute to a bog or stumble.I would look at the secondary operation.Also narrow down wether it's a rich or lean bog/stumble.Black smoke out of tailpipe at time of bog is rich.Lean would be white smoke.If you have a vacuum gauge connected to the engine and you can see the reading at the time of the bog,the vacuum reading can tell you if it's the primary or the secondary circuit.Make only one change at a time to avoid confusion.Maybe try Edelbrock website for specific tuning.
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cam specs are 256 intake 262 exhaust, duration at .050 is 210 intake 218 exhaust. lsa is 111 degrees lobe lift is .299 intake and .298 exhaust. im getting about 17" of vacuum at idle. I have the stock dualplane manifold and ported stock truck exhaust manifolds. Im not noticing any smoke black or white, but I pulled the #1 spark plug and its white no coloring what so ever, I put slightly smaller metering rods in the carb to richen it up a bit WOT got better but mid throttle criusing got worse. Secondary circut seems to work fine. Ill drive around with a vacuum guage and let you know what I find
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My fuel pressure was running too high, I didnt know eddys needed 6 psi or less I must have skipped that part in the manual lol. I installed a pressure regulator and it solved the stumble. Thanks for the info.
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