Author Topic: Uprating my 1969 Mach One S-Code  (Read 2832 times)


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  • Mustang: 1969 Mach One S-Code
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Uprating my 1969 Mach One S-Code
« on: May 29, 2012, 08:06:31 PM »

I have just bought this Black Jade Mach One 390 S-Code:

I would like to make the engine sound to my liking, and for this I have a few questions for you:

I am keen on keeping the car original, so any mods must be reversible, for the sake of resale.

Essentially I'm looking for 2 things from my engine sound:
1) I have always loved the loud bassy throaty rumble of classic dual-chambered Flowmasters
2) I want a "big cam" lumpy hunting idle, which makes the car sound restless, aggressive and belligerent.
This is the kind of lumpy idle I'm looking for:
1969 mustang mach 1 351w big cam idle pt. 2

- Regarding the exhaust, below are photos of the exhaust on a 1969 Mach One 302 that I wanted to model the sound of, because it was PERFECT to me. I note the presence of headers, an H pipe, and particularly small Flowmaster mufflers.

I found these headers:
And this Flowmaster exhaust:

- Do these headers and exhaust fit together?
- I note the Flowmaster mufflers are Super 44's. These are considerably bigger than the 302 exhaust I'm trying to copy. How come I can't find an exhaust with those very small Flowmaster mufflers?? :-/

Regarding cams and lifters, I found 3 possible profiles:
a) (288 duration, 537 lift)
b) (272, 533)
c) (266, 516)

In the video of the blue Mustang (above), the owner says "it is a crane energizer cam it has 520 lift and a 292 duration but crane cam does not make this cam anymore i dont think, i bought this cam a few years ago".

I think I would want b), because I'm looking for a streetable car with a what you might call a "mild race tune", retaining strong torque from 2000rpm (I am willing to sacrifice torque some below 2000 in exchange for getting the lumpy idle I want). I feel that cam a) might sacrifice too much bottom end grunt.

While I'm at it, might uprating the carb + intake manifold yield a large and cost-effective hike in power and torque?Can I expect very noticeable gains, or would you need a timed run to spot the small increase?

I think a dual plane intake would be better for street use than a single plane (but can I still get a lumpy idle with a dual plain??).

Might this be a good carb + intake combo?
What difference can I expect from stock? (in terms of numbers and feel)

Thanks for your comments and input on these various points.



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Re: Uprating my 1969 Mach One S-Code
« Reply #1 on: May 30, 2012, 11:14:54 AM »
Okay, let me take a shot at this.  The headers you picked are very nice, Hooker headers have always had a really good sound to my ear.

Of the cam choices you listed I like the first but think you will like this even better

I don't like prefab exhausts-I prefer to have an exhaust shop hang my system, it isn't any more expensive than what you are looking at.  I would look for true duals and 3" pipes.

As to mufflers, I prefer Magnaflows as I think the Flowmasters all drone at certain speeds in my experience.

Intake looks okay though I am not all that familiar with FE engines.  I tend to prefer a Holley carb, but some folks like the Edelbrocks tuning features.  Be aware nothing works out of the box as well as it does following good tuning. 

Nothing will give you an exact power estimate, but compcams does have a calculator you can play with.  I'd expect substantial gains with the listed mods and  I'd guess horsepower 75-100hp over stock, but that is just a wag


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  • Mustang: 1969 Mach One S-Code
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Re: Uprating my 1969 Mach One S-Code
« Reply #2 on: June 02, 2012, 08:22:35 AM »
Thanks for your comments.

I have had the car inspected, and it turns out to already have Flowmasters! And the idle is lumpy enough. :-)

Because the exhaust was my trigger to make some changes, I have decided to wait until I receive that car and drive it a bit to decide if changes are in order.



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