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Advice needed for gaining traction and heater system.

1011 Views 5 Replies 6 Participants Last post by  Driveway
I have a 66 with a 289 and a manual 5-speed transmission. It's great fun by I can't even drive it across a puddle without it losing its damn mind. I think I'd like to start by installing a sway bar to tighten up the handling a little bit but could use some recommendations. Also, even though the heater core is in great shape, can't seem to get much in the way of blowing air from it. Is this kind of normal for older mustangs, or is it possible the blower motor is going out? Any recommendations on beefing up the heating system?
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What tires are you running? Are you getting heat or just not enough flow through the vents? What temp thermostat is installed?
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Welcome to AFM, Hezzaw!

These early cars all have one massive problem that should probably be addressed before anything else, and I think you'll be amazed at the difference.


Factory specs are for bias-ply tires, which did not appreciate caster. However, modern radials need it for stability, feel, and handling. I'll give you modern specs to use at the end here.

Your caster is adjusted with two rods attached to the lower control arms, and tightening them up brings the arms forward, adding caster. However, too far forward, and the tires will begin to rub! With stock suspension, the best way to deal with that and put your tires and wheels squarely in the middle of your wheelwell, you will need to add shims to the front of the upper control arm, bringing the top back a little. Yes, it's a pain in the rear. But it works.

While you're at it, you may want to address another problem: the factory suspension was designed to understeer, for safety reasons. They went full overkill on that, and put the upper control arms at a steep angle to the bottom arm. As a result, when cornering hard, the outer tire's suspension is compressed upwards. The top of the tire tips out, the bottom rolls in, and the tire either lifts its tread from the road, or rolls over onto its sidewall a bit. This is not conducive to sharp handling.

Klaus Arning and Carrol Shelby devised a very simple way to fix this, and introduced "the Shelby drop" or "Shelby Mod" as it is commonly known. By using a template, you can drill two new holes in your shock tower, and mount the upper control arm lower. Ideally, you may want to move it back a little too, to help add caster without shims. Your car's nose will be about 5/8" lower when it's all done, but more importantly, when driving, your car will stay planted while cornering, and enjoy less body roll too.

Combined with a 1" front swaybar, some good shocks (I recommend Bilstein), and the following alignment specs, it's remarkable how your car's handling and ride quality will improve.

1/8" toe-in. (1/16" on each side) This takes up all the slack in your suspension and steering when your car is moving forward, so that the tires are perfectly parallel when going down the road.

0 to .5 degrees camber (tires should be mostly straight up and down, or just barely tipped "in" at the top to brace against turns. More camber means more uneven tire wear, so for street cars, less is more.

About 3 degrees of positive caster. If you have power steering, 4 or 5 degrees is even better. More caster will require more steering effort, but offers far better high-speed stability, and even adds a little camber when turning.

Edit: I should also add, there are lots of aftermarket parts to improve your stock suspension too. They make upper control arms with roller spring perches that even have built-in geometry correction so you don't have to drill more holes to get the benefit of the "Shelby mod". The factory strut rods for lower control arms use two big rubber donuts to hold them to the frame. Those add slop to the handling, and always degrade over time too. Adjustable strut rods are available that mount directly to the frame without a flexible donut to hold it, offering much more precise steering. When combined with roller perches, ride quality is significantly better than stock. If you're interested in any of these better parts, check out
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First thing that comes to mind is the age of the tires. After about ten years they are hard as a rock.

I remember many a cold winter trip in my girlfriend's old '66. My solution? Marry her and sell the car!

Seriously though, a lot can be done with these old cars to have them heat up the passenger compartment better. Install a new 195F thermostat, followed by a good chemical flush of the system to clean up the clogged heater core.
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I suggest you get the front end on jack stands and take a good look at all the steering and suspension parts. This includes ALL the rubber items. The lower spring perch too. You will be surprised at what you find. The steering box may need to be adjusted. Two things to check: Does the steering wheel move up and down in the column? Does the steering wheel have a dead zone at center where the wheel turns but not the tires? There are separate adjustments for each.

The heater box may be full of leaves and crud. It is not easy to clean out. Make sure the 3 cables are working and adjusted. There are several doors in the heater box, they may be broken or rusted.
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