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1973 351w Emission Control Removal
#1
I have a 1973 Mustang with a 351w motor in it. A guy told me that I can gain hp by removing the emission control componets on the engine. I know that after '71 the HP ratings went way down on 351engines due to stricter emission standards. If this is true then I would like them deleted. I am a novice, but a quick learner and good with tools, its just I don't really know what to look for or where. Any help will be greatly welcomed. Pics or websites are encourged. Thanks...
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#2
It's not as though you remove the erg valve and your horsepower goes up. The engines were built with open chambered heads and lower compression ratios.

[Image: 2rr7aiv.png]

Just cruising along minding our own business when BAM!!! The LAWS show up.
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#3
And the camshafts where ground 4-6' retarded [off the top of my head]. the cast exhaust manifold don't do a lot for performance either. a free breathing air cleaner, a set of headers, and a good ignition system will get you started after that you need to open up the engine, new cam, timing gear set, aftermarket intake manifold. It go's on from there..

Anything is possible, It just takes time and MONEY....
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#4
Dont forget the heads. The "smog heads" had really small ports. Similiar to what you would see on a 289/302. An intake, exhaust and maybe carb would definitely help. But you're not going to see big numbers till you change the heads and cam. Most people here seem to be Cleveland fans (unless you have a big block), but I am pretty partial to the Windsors. I grew up with the 5.0L's and had a stroked Windsor.
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#5
jrgeorge1112;107465 Wrote:I have a 1973 Mustang with a 351w motor in it. A guy told me that I can gain hp by removing the emission control componets on the engine. I know that after '71 the HP ratings went way down on 351engines due to stricter emission standards. If this is true then I would like them deleted. I am a novice, but a quick learner and good with tools, its just I don't really know what to look for or where. Any help will be greatly welcomed. Pics or websites are encourged. Thanks...

1, I didn't know 73 Mustang was available with a Windsor....

2. There was a whole series of changes to the motor:
- restrictive head
- lower compression due to pistons and head
- cam change

not to mention the difficulty in getting:
- 3.25+ rear end
- High RPM Torque Converter

3. With the Windsor, you have restrictive intake and exhaust.

Your ideal solution would be to do a 302 Boss conversion on your 351W.

But, in regards to little things, I cannot imagine remove any of the pollution controls is going to gain you a whole lot.

What are the issues with the motor now besides power? Is it eating oil, smoking, or anything else?

Is this a California car? I don't remember my 73 Mustang having anything on it except the silly dual vacuum ports on the advance.

In other words, you have your work cut out for you.

[Image: 11jmcuc.png]
351C Bold Manners, Brash Attitude
Favorite Teams: Michigan Wolverines and Whoever Is Playing Ohio State.

When I drive past a herd of cows, the cows MOO at me
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#6
Or you could keep it simple and get a set of AFR heads (AFR-185 or AFR-205 depending on what you want to accomplish). Those heads with an Edelbrock dual plane Air Gap intake are a great combo to build upon. Then, if you were ever to rebuild that Windsor, you just need the short block and appropriate carb.
You really just have to figure out what you want to end up with..
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#7
cazsper;107649 Wrote:Or you could keep it simple and get a set of AFR heads (AFR-185 or AFR-205 depending on what you want to accomplish). Those heads with an Edelbrock dual plane Air Gap intake are a great combo to build upon. Then, if you were ever to rebuild that Windsor, you just need the short block and appropriate carb.
You really just have to figure out what you want to end up with..

A RPM Air Gap on a 351W won't fit under the stock hood on a 71-73 Mustang, been there tried that. It will fit if you want to cut a hole in the hood and put a scoop over it. The 351W I put in my Mustang to replace the 302 will barely fit a regular Edelbrock Performer under the hood.

my current rides
1973 Mustang Coupe
1989 Mercury Cougar XR7
1973 Mercury XR7 Cougar Convertible(sold)
1966 Mercury Comet 202
1985 F150 4x4
1962 Ford Fairlane 500
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#8
I'm surprised. It fit under the hood of my '68. I figured there woukd be more room in the 71-73.. How about the RPM Performer? I know it's lower than the Air Gap.
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#9
cazsper;107852 Wrote:I'm surprised. It fit under the hood of my '68. I figured there woukd be more room in the 71-73.. How about the RPM Performer? I know it's lower than the Air Gap.

I don't know about a RPM, it might fit. I tried the Air Gap on my 73 and it was about 2-3" too high. I am using a flat hood too, so a ram air hood might give the clearance needed. With the regular Performer intake and a thin 2"tall air cleaner I have about 3/4" hood clearance on my 73 with a 351W. If I could use a drop base air cleaner I could gain a inch maybe two, but my MSD distributor won't let me use a large diameter air cleaner with a drop base. What would be sweet is if I could use the Air Gap intake. I might be able to get some clearance with a different motor mount a ramair hood and a different distributor. I would really like to use a better intake on my engine.


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my current rides
1973 Mustang Coupe
1989 Mercury Cougar XR7
1973 Mercury XR7 Cougar Convertible(sold)
1966 Mercury Comet 202
1985 F150 4x4
1962 Ford Fairlane 500
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#10
First. Let's confirm if it is a 351c or 351w.
A 351C has 8 valve cover bolts and the top radiator hose is connected to a housing bolted to the engine block. It it verticle to the engine in its approach.
A 351w (or any of that family) has 6 valve cover bolts. The top radiator hose is connected to the intake manifold and is horizontal to the engine in its approach.

Not sure? Post a pic.

If you have a 351w it was swapped in. Certainly not out of the question for a 40 year old car. A 351W would be a pretty quick bolt in for a car that came originally with a 302.

'Mike'
73 Convertible - 351C/4V CC heads/4bolt/forged flat tops/comp 270/rhodes/mallory unilite/tri-power/hookers/glasspacks/c6/3.50 limited slip/Gear Vendors/Global West sub frames, strut rods and shelby style traction bars/ Rear sway bar/tilt steering (not original)

Pics of modifications included in:
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