Ford 351C question

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Joe - 13 Apr 2005 13:51 GMT

I have a 1972 Mustang with a 351C, 4-V. I'm replacing the stock
Motorcraft 4300D that's on it with an Edelbrock 750 cfm, because the
Motorcraft float is screwed up and the secondaries are frozen shut. As
the car is now, it won't start with the stock carb. I need to
determine if the distributor vacuum port on the stock 4300D carb is
timed (no vacuum at idle) or full (vacuum at idle). Since I can't
start it with this carb on it, I can't do a simple vacuum test. Anyone
know if this car has either timed or full distributor vacuum? Thanks.

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Wound Up - 13 Apr 2005 20:29 GMT

Joe,

You might do well to post this and other questions about your car on
alt.hi-po.big-block-ford-mercury. Your car and engine is definitely
on-topic over there. There are lots of folks with lots of expertise with
this stuff. I wish *I* had some to give you on this specific question...
good luck, regardless!

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Wound Up
ThunderSnake #65

>I have a 1972 Mustang with a 351C, 4-V. I'm replacing the stock
> Motorcraft 4300D that's on it with an Edelbrock 750 cfm, because the
[quoted text clipped - 4 lines]
> start it with this carb on it, I can't do a simple vacuum test. Anyone
> know if this car has either timed or full distributor vacuum? Thanks.

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one80out@hotmail.com - 13 Apr 2005 20:35 GMT

> Anyone know if this car has either
> timed or full distributor vacuum?

I don't know what the specs say, but I always use the timed vacuum, aka
ported. This gives you only base timing for startup, which makes it
easier on the starter motor. Then you get the vacuum advance on
tip-in, which is the whole purpose of vacuum advance: to give you more
power with less fuel. Whether ported or full, the vacuum effect goes
away at WOT.

180 Out

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