1968 Mustang info needed

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Ron Patterson - 10 Oct 2007 21:53 GMT

I have a 1968 Mustang 302 V8 power train in a 'Ford Exotic'. Four barrel
carb and 4 speed.

Can someone provide me with the following factory recommendations:

Timing in degrees BTDC at idle (625 rpm) and fully advanced?

Thanks to all respondents,
Ron Patterson

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.boB - 11 Oct 2007 19:02 GMT

> I have a 1968 Mustang 302 V8 power train in a 'Ford Exotic'. Four barrel
> carb and 4 speed.
[quoted text clipped - 5 lines]
> Thanks to all respondents,
> Ron Patterson

Depends on a lot of facters. Ford starts with 12*
basic, about 24* mechanical, and 6* vacuum.
BUT - those specs are 40 years old. Depending on
where you live, what kind of gas you use, and what mods
you've done, those specs are probably invalid.

So, here's how to set the timing in your car:

Base: Connect a vacuum gauge to the manifold. Set the
timing where you get the most vacuum.
If you don't have a vacuum gauge; set 1/2 a glass
of water on the fender. Set the timing where the
ripples in the water are the smoothest.

Mechanical advance: Advance until you get pinging
under acceleration. Then back off 2*.

Vacuum advance: Advance until you get pinging on light
acceleration, then back off 2*.

Signature

.boB
2006 FXDI hot rod
2001 Dodge Dakota QC 5.9/4x4/3.92
1966 Mustang Coupe - Daily Driver
1965 FFR Cobra - 427W EFI, Damn Fast.

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Ron Patterson - 12 Oct 2007 05:40 GMT

Hey - great info. Stuff I never heard before. Thanks much.

Please to educate me a bit. I thought manifold vacuum would only be
dependent on cam timing (and of course engine condition). Please explain
how the ignition timing effects manifold vacuum.

Retarding from pinging is probably the ultimate way to set timing.
Unfortunately my hearing is so bad that I never hear pinging so I do need a
baseline to start. I have a dual point mechanical distributor - no vacuum
pot and will be running 91 Octane.

Thought I would start about 2 degrees retarded from the factory settings.
Assume from below that would be
12* at idle + 24* mechanical = 36* fully advanced?

Ron Patterson

>> I have a 1968 Mustang 302 V8 power train in a 'Ford Exotic'. Four barrel
>> carb and 4 speed.
[quoted text clipped - 23 lines]
> Vacuum advance: Advance until you get pinging on light acceleration, then
> back off 2*.

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RD Jones - 13 Oct 2007 00:14 GMT

> Hey - great info. Stuff I never heard before. Thanks much.

Please take some of that with a large block of deer-lick salt.

> Retarding from pinging is probably the ultimate way to set timing.
> Unfortunately my hearing is so bad that I never hear pinging so I do need a
> baseline to start. I have a dual point mechanical distributor - no vacuum
> pot and will be running 91 Octane.

Although the '68 302 is a decendent of the 289 HiPo, I don't think it
is stock
with the dual point. It should have the vacuum advance. Any other
hardware
on the engine been changed ?

Factory spec for the '68 302 4V in a Mustang is 6* BTDC, with the
stock distributor.
The Fords that came with factory dual-points used more initial lead:
12* BTDC.
(the dual points lacked the vacuum diaphram)

Also bear in mind that this engine is 10:1 compression and should be
running
premium in any case.

> Thought I would start about 2 degrees retarded from the factory settings.
> Assume from below that would be
> 12* at idle + 24* mechanical = 36* fully advanced?

I couldn't find any spec from Ford for fully advanced, but any typical
V8
engine will not benefit from more than about 36-38* maximum advance.

In the absence of a vacuum advance diaphram 12* BTDC is a good
starting point.
I'd still check for "all-in" at about 3500-4000 rpm not to excede 38*.

good luck
rd

> Ron Patterson
>
[quoted text clipped - 28 lines]
> > --
> > .boB

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