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#1
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Most feedback in fb is suggesting my rear transfer slot is over exposed with symptoms I’m explaining. However the spring in diaphragm is not pressing the rod down hard enough so maybe I need to replace it a stiffer spring ? Wouldn’t want it flopping around . I dunno maybe the screw adjustment might tighten it up ?
Yes I heard that the pv or block off pv might have to thick of a gasket ? That I should try lining up metering block to body with out gasket and look for issues ? Same with main body to base plate . Also replace pv just to rule Out . Power went out here so will Have to try tomorrow . Thanks for suggesting the indent mark may be present .
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69 Gto, 390 posi gears,th400 w/jim hand converter/406 pontiac/#64 HEADS/ 10:1 compression/ 190 PSI with/ TRW 160 thou domes / hooker headers 1 7/8, PRW 1.5 rockers, 405 Crower Springs, Holley 750 vac with proform upgrade, Performer RPM on points / 284 H Single Pattern Crane |
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#2
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Have you tried adding secondary idle air by adjusting the secondary throttle stop? That’s usually all that is needed to clean up the idle and restore function to the mixture screws.
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Triple Black 1971 GTO |
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#3
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Secondary transfer slot should not be exposed at idle. Starting point is to back off screw until it does not touch secondary arm. Then screw it in until the screw touches the arm, then go another 1/2 turn.
The IFRs looks large to me, but I can't see the actual restriction. Stock IFR on that carb is likely about .028 to .030". Front transfer slot should be square at curb idle. Starting point for 4-corner idle is to open the screws 1.25 turns. Close them in 1/8 turn increments for highest vacuum. A 4-corner usually ends up with idle mixture screws 1/2-3/4" turn open from seated. What are LSAB sizes? 70? High IFRs and 3 emulsions. Low speed AFR is going to be unstable. Cruise mixture is going to be rich. WOT will be about 13.1
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I could explain all this to the girl at the parts store, but she'd probably call the asylum. White '67 LeMans 407/TH350/Ford 3.89... RIP Red '67 LeMans. 407/TH400/Ford 3.25 Last edited by chiphead; 03-26-2026 at 01:37 PM. |
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