Eugene, Nope, the distro takeoff's connected to the top of the front carb bowl. I have a dial-back timing light and checked it all from below idle up to
3500rpm; looked good. The distributor's a Mallory Comp9000 Unilite with an MSD coil and Accel wires. Drink Where is your distributer vacuum connected to? I accidentally (read
> stupidly) connected the vacuum advance to manifold vacuum rather than the
> carb pre butterfly outlet. It killed the engine response like yours. >
> Have you checked your ignition timing at idle (about 8 degrees) then up to
> 3000 rpm to see what the advance is doing - should be about 30 deg total
> advance or so?
>
> My rule in troubleshooting - if it looks like a carb problem: check the
> ignition system. If it looks like an ignition problem: check the carb.
> Works 90% of the time.
>
> You never said if you have a HEI distributer or points. If it's points > check
> the gap.
>
> James Dr>
>> Hi Guys,
>> Got a Holley 650 double-pumper on "Dad's hotrod" with some probs >> tuning.
>> Upon depression of the throttle, my fuel/air ratio gauge shows that the
>> mixture goes way lean and the engine goes into lean misfire and dropped
>> power. Eventually it richens back up as the RPMs slowly increase. Not
>> talking about the accelerator pump, just giving it a little more gas >> while
>> driving.
>> Bought the carb from my machinist in the original box in like-new
>> (visually) condition. Here's what's new and ruled out: high-volume fuel
>> pump, fuel filter, fuel regulator and pressure gauge, float needles & >> seats,
>> jets (just to be sure), 6.5" power valve (like the original). both
>> squirters appear to pump fine but the problem occurs when you slowly roll
>> into the throttle and it happens really quick (very throttle sensitive).
>> It's a moderate, street performance SB Chevy that makes about 10.5" >> vacuum
>> at idle. I know the PV should move up to 8.5" but rolling into heavy
>> acceleration (vacuum below PV opening point) doesn't overcome the lean
>> condition either.
>> Two last things are that idle mixture is pretty un-responsive to idle
>> mixture screws, even when idle speed is as low as the engine will >> reliably
>> rev. Second, main jets were very, very rich at stock 67's (primary) and
>> still a tad on the rich side with 65's.
>> Dirty passage somewhere? Higher vacuum power valve needed and drill >> the
>> PVCR's? I'm a little stumped.
>> Best Regards,
>> Drink
>>
>> '87 TransAm (No computer controls)
>> Holley 650cfm double-pumper
>> Victor Jr. single plane
>> 186 heads, fully ported with 2.02 valves
>> 218/228 roller cam
>> 1.6 magnum rockers
>> 10:1 KB pistons
>> Mallory Comp9000 distributor
>> Hooker SuperComp headers
>> 3.73 gears
>
> --
> Eugene Blanchard
>
formatting link
Parts, Performance, Passion> News for Motorheads