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I’ve got a 67 mustang with a 289, 4 barrel carb, 5 speed with a. 9” rear end. I understand it’s not a high horsepower motor so the question is. Should I invest in a pro comp cam, new lifters and springs, timing chain, headers and new gears? I think I’m pushing around 210-225 horsepower currently. I’m told this may get me to closer to 300. Is it worth the investment or should I just do a motor swap? I’m not looking for high top end speed just a quick off the line set up to drive on the weekends.
 

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to get 300hp out of a 289 these days is pretty easy, you just need the right combination of parts. the right cam heads, headers, and intake will get you there. the gears will get you off the line nicely, and the overdrive will keep the cruise rpms down to a reasonable level.
 

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289s are great little engines. If it runs good, modify it.
 

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if your going that deep, i would either port the exhaust side of the heads or get some 58cc afr 165s (and even mill them a bit) - porting the exhaust, a valve job and adding new springs (which you will need with the new cam) may run you around $700 (I paid that recently for the same work on some D0OEs) the afrs would run you $1700 or so - i would not bother with the cheap ebay heads....get some nice tri Ys, a cam with 220 or so int dur at.050 and some 3.25 or 3.55 gears and you will love the car - dont forget to tune the carb an dist curve for your new combo.
 

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if your going that deep, i would either port the exhaust side of the heads or get some 58cc afr 165s (and even mill them a bit) - porting the exhaust, a valve job and adding new springs (which you will need with the new cam) may run you around $700 (I paid that recently for the same work on some D0OEs) the afrs would run you $1700 or so - i would not bother with the cheap ebay heads....get some nice tri Ys, a cam with 220 or so int dur at.050 and some 3.25 or 3.55 gears and you will love the car - dont forget to tune the carb an dist curve for your new combo.
That's pretty much my engine. I had '65 heads that I had pocket ported and then switched to AFR 165's that had been milled down to about 53cc IIRC. I have my rev limiter set at 6,200 and it pulls hard to there.
 

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I’ve got a 67 mustang with a 289, 4 barrel carb, 5 speed with a. 9” rear end. I understand it’s not a high horsepower motor so the question is. Should I invest in a pro comp cam, new lifters and springs, timing chain, headers and new gears? I think I’m pushing around 210-225 horsepower currently. I’m told this may get me to closer to 300. Is it worth the investment or should I just do a motor swap? I’m not looking for high top end speed just a quick off the line set up to drive on the weekends.
Investment? If you are careful, You could keep this under $1000. Worth it? You can get to Dairy Queen at insane speeds. If there are curves on that road, you had better do the Arning Drop.

While I have the C3OZ-6250-C mechanical cam in my own car, mechanical cams are not for everyone. The C9OZ-6250-C hydraulic cam provides very similar performance.

For this upgrade, you will need:

•C9OZ-6250-C camshaft
•Cobra or Performer RPM intake manifold
•Autolite, Summit, or Edelbrock 600 cfm carburetor
•14" open air cleaner
•Distributor recurved to BOSS 302 specifications
•Dual valve springs (recommended)
•Screw-in rocker studs (recommended)
•Heads port-matched to exhaust (or aftermarket heads)
•289HP exhaust manifolds or headers

This combination has been dyno tested at 323.5 hp @ 5300 rpm.

Nothing else is required. No whiz-bang million volt coil, 10mm wires, etcetera.
 
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It’ll likely take heads/head work to get over the 300 mark, but that doesn’t mean it’s not worth doing what you described. If you have 2,80 or 3.00 gears, 3.73’s will be a nice fit for the T5.
 

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I like to start to with gears. So, I would suggest first installing a bigger gear in the diff. Make it limited slip while you're at it. I went with an Eaton Truetrac and I really like it. You'll be AMAZED at the difference. And you'll be ready for any other engine mods without doing the one wheel peel.
 

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1968 Mustang Fastback, 289, T5-5 speed
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If you already have a T5 I suggest the 3.55 or 3.73 gears first.

What do you have for gears right now?
 

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I pulled my open 2.80 third member out and got a 3.55 trac-loc form 8and9incfordrears. Built and shipped right to my door. Included the friction modifier. Dropped right in. Easy peasy.
 
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Discussion Starter #13
Wow!! I didn’t expect all of the help so fast gentleman. From what I’ve read the investment seems worth doing but make sure I get a set of good heads. I’m upgrading the gears to 3:55 To answer the earlier question, I’m not sure about the current gears, I bought the car about two months ago. I do know the motor is the original block but I’m told it’s been rebuilt.

One last question since you guys are so bad ass and helpful. I’m getting some road drift in the steering when I get above 40 mph. I looked over the front suspension and the bushing control arms and ball joints all look good. I only have about 1-1.5” of play. Speaking to another mustang buddy of mine, he mentioned the alignment may be thrown off which is pretty common. Thoughts?
 

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could be the steering box.......
before you change gears, what rpm are you at in 4th gear at 60mph? what size rear tires do you have on it? someone may have upgraded the gears already
 

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Pretty bad ass! I’m hooked. I’ve been reading through the other threads as well. Lots of good info
Anything you want to do, someone here has already done it, and will
Walk you through it.
 

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Discussion Starter #18
could be the steering box.......
before you change gears, what rpm are you at in 4th gear at 60mph? what size rear tires do you have on it? someone may have upgraded the gears already
Awesome! I’ll check the box and look into the rear gears. I don’t have a tach gauge but first and second gears are really low. I can run 75 mph on the freeway with super low rpms in 5th gear.
 

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One last question since you guys are so bad ass and helpful. I’m getting some road drift in the steering when I get above 40 mph. I looked over the front suspension and the bushing control arms and ball joints all look good. I only have about 1-1.5” of play. Speaking to another mustang buddy of mine, he mentioned the alignment may be thrown off which is pretty common. Thoughts?
One of the failings of the original design is the limited caster that can be “dialed-in.” The modern spec recommended by most is for +3º or more caster. This is needed for that “return to center – hands off steer straight” feel of modern steering. To accomplish this the strut rods need to be adjusted to pull the lower control arm forward with the result being the tire is moved forward sufficiently to rub the fender. The solution is an upper control arm that re-positions the ball joint back to give some build in caster. Opentracker has that, but at a price. Street or Track has that, as does Global West and Hotchkis.
If you’re only driving to the Dairy Queen, or the local car show, this is not important. But if you plan to drive distance it is necessary.
In any case, the original alignment specs are terrible for modern radial tires. Getting an alignment with more modern specs will help you even if the there are limitations.
 

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Have a performance alignment done or better yet for less money buy a gauge and learn to do it yourself. Get some positive caster in that thing and your wandering will improve greatly. Do an Arning drop. Plenty of info here on what and how and I am sure someone will pop up some thread links for you.
 
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