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Discussion Starter #1
I just ordered a rebuilt distributor for my 66 coupe 289. It is the correct single point vacuum advance type.

Two questions.
1. Where does the vacuum hose from the advance, connect to? I assume it’s on the carb. I have a Holley 4bbl. It has two capped off nipples for vacuum lines. If you’re looking at it from the front, one is on the front-most, top left corner, sticking straight out to the left. The other is about 2 inches behind that, coming out toward you at an angle. Is one of these the spot?

2. How hard is it to swap distributors? Does it just pull out? I know I’ll have to reset the timing, but is there anything else major involved?

TIA

DAVE
MCA# 48565
 

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Here's what always works for me:

1. Remove the distributor cap. Turn the engine over so the rotor faces directly front-wards.
2. Mark the position of one of the hold down clips on the intake manifold with a crayon.
3. Remove the hold distributor. Install the new distributor using the indexing as done above.

Not knowing which model Holley you have, I'm guessing one of the vacuum lines is timed vacuum (fed by a port above the throttle plate) usually used for EGR. Connect the vacuum line to whichever port has manifold vacuum at idle.

Good Luck.


'66 A-code Fastback (therapy)
'89 Town Car (SWMBO D'driver)
'87 Caprice (as req'd by Hagerty)
 
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Discussion Starter #3
2 things. Im replacing an aftermarket 'Mallory' dist. with the original Ford one, does this make a difference as far as the positioning of the rotor and hold down clip?

Second, someone else told me the opposite of your post on where the vaccum hose should go. they said...For your vacuum advance, you'll want a ported vacuum (one that is NOT present
during idle).

So which one is it? Vacuum at idle or not?
 
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Discussion Starter #4
Ported vacuum is correct.
On most Holleys it is the vacuum port coming out of the right side of the primary metering block just above the idle mixture screw

Greg B
 

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Instead of using a clip to index the distributor, use one of the spark plug towers on the cap. Index to the same one when installing the new distributor. I have always used a non-ported source. This way I would have vacuum to the advance unit during decelleration and idle, with enough retard during throttle opening to prevent spark knock and hesitation. It's confusing sometimes, but the purpose of vacuum advance is to provide advance in reverse proportion of engine load; that is, no advance at WOT and high advance at closed throttle.

'66 A-code Fastback (therapy)
'89 Town Car (SWMBO D'driver)
'87 Caprice (as req'd by Hagerty)
 
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