hey guys!

im 17 so im somewhat new to this hole old car thing, my father and i thought it would be cool to get a project car. So we found and picked up a 1973 plymouth duster. Its got a 225 slant six in it. I call it my gutless wonder because i have a hard time reaching the speed limit on the freeway. My father says that eveyrthing is fine under the hood but its just old and its a slant six, thus its slow. So i was wondering if anyone could help me out by giving me a website or a list of parts that i can get to help increase the hp of my duster. I have some money saved up to spend on it but dropping a v8 in it is out of the question so my father says. So can anyone help me out??

-Bryce

Welcome onboard! We'll try to help you as best we can.

The first thing you should do is get a factory service manual (should be easy to find on eBay or from www.autolit.com -- you can use a '73 Plymouth/Valiant or '73 Dodge/Dart manual, but make sure it's a genuine Chrysler-printed manual, not a Haynes or Chilton's book.). Make sure the engine is in proper tune and everything's in good order. There's lots to check. Carburetor condition and adjustments, air and fuel filters, PCV valve and crankcase breather, tappet clearance, ignition timing, vacuum and centrifugal spark advance mechanisms, thermostatic air cleaner function, EGR function, maniifold heat control valve function, choke function.

Once you've done that, there are some easy and inexpensive modifications you can make that will make the car a bit peppier. Once you've done that, there are some more extensive modifications you can make that will make it nice and snappy. It doesn't have to be slow just 'cause it's got a Six!

It sounds like you're new to working on old slant-6 cars. If that's true, then I recommend you buy and read two other books, as well:

* Stockel and Stockel, "Auto Mechanics Fundamentals", an issue before approx
1980, see Here

* Petersen's Automotive Troubleshooting & Repair Manual, 1975. See
Here

The Stockel book explains how everything works. The Petersen book has LOTS of pictures and explains how to fix everything. The factory service manual contains all the data and settings for your particular car.

In the meantime, to get you started, here are two minor modifications that will add a little bit more pep to your car:

1) Bypass the OSAC valve. It is located on the firewall, on the passenger side. There is one hose running to it from the carburetor, and another hose to the valve from the distributor. To bypass the valve, run a properly-sized vacuum hose from the carburetor directly to the distributor, using the same port on the carb and distributor that the original hoses (to the OSAC valve) hooked to.

2) When you're ready to put in new spark plugs, use NGK ZFR5N or Autolite 985, gapped to 0.040". These have a special electrode configuration that helps give more complete combustion, which in turn helps make a little more power.

Hey Bryce!

Welcome to the Forum. It's great to have you here. That's cool your father got you a Duster as a project vehicle and not a Honda or something!

Like Dan said, there are many basic things that need to be checked first. You could add all sorts of cool and expensive things to your car and it would still be slow because you don't have the basics worked out first. Luckily, your '73 Duster with a Slant 6 is a great way to learn those basics without needing a degree in computer programming or nuclear physics or anything.

Follow Dan's advice, learn the fundamentals, tinker a little bit and get to know your car. Then, as you get more familiar with it and want to try more advanced things we can talk about adding more power.

As you look around the site and get more familiar with things you'll see that "old and slant six" does not have to mean "slow"!

Welcome again to the Forum! We all love to see new people getting involved in the Slant 6 thing. keep us posted on how things go.

_________________
Rob

I’m Mater
The Kentucky Poser

Welcome Bryce, as Dan and Rob says, you need to check in deep the engine and transmission bussiness and learn how they work, after that you can start adding some extra horses.

I can tell you that a Slant is not weak, is a hidden monster, my mexican Valiant Duster 1971 kicks Stratus R/T 2002 so easy that gets boring also Hondas Civis, Accords, Jettas A4 VR 6 Toyotas, Intrepids, and is long go.

You get beaten at the start, but some meters ahead you starts getting a lot forward. The true problems is when you are trying to brake with drum brakes.

Also Dan, What I do if I don´t have a OSAC valve?

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Mopar Muscle is well defend by Slant Six!

Valiant Duster 1971

Right, this was an emission control device not used outside the US/Canada.

Ok Dan I was starting to worry.

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Mopar Muscle is well defend by Slant Six!

Valiant Duster 1971

Get yourself a good timing light and check your timing. That might be your problem. Timing for 73 is TDC. Try to get it as close as possible to that.

My stock 74 Duster will run 123 MPH wide open, so slants are not slow.

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

My Slant got from 0-60mph in 6.5 seconds, and gets easy to top speed without problems.

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Mopar Muscle is well defend by Slant Six!

Valiant Duster 1971

My mostly stock slant six Dodge aspen runs 19 seconds in the 1/4 mile. That's slow for a drag car, but plenty of fun around town. I still have a million things to do and I expect to shave a second per year off my 1/4 mile times over the next 5 years. (I can dream can't I?) A 14 second slant six street car will kick ass!

I suspect that something is wrong with the engine, since even my heavy truck doesn't have any problems maintaining highway speeds with a slant six. (unless I'm hauling a car behind it.)

Once the engine is fixed, a gearing change is commonly needed to reveal your engines potential at a stoplight. From the factory, most slant six cars were geared for good gas mileage, and not quickness.

Check out the articles section of this website and some of the cars that guys race. Lots to learn and lots of good people to help you.

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1980 Aspen 225 super six

avenger 2040
you said you slant will beat an a4 vr6 jetta i have a hard engouh time beating a built a2 gti 8v so waht do you run in the 1/8 or 1/4 and what did you do tho you engine thanks a lot
-Ben

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http://www.geocities.com/slantisxduster
http://www.mattcrane.net

Nothing really, bigger, increased exhaust flow, iridium (forgot how bujías is in english, you know the ones that makes the spark for pistons), both vacuum valves in carb open, and thats all to beat a Jetta A4 VR6 in 1/4 mille, just you stock 225 with 185 HP and 210 Torque.

_________________
Mopar Muscle is well defend by Slant Six!

Valiant Duster 1971

bujías = spark plugs.

Thanks Dan!

_________________
Mopar Muscle is well defend by Slant Six!

Valiant Duster 1971

I dunno about 123mph,but she should go near 100 in proper tune.I've had two 73 golddusters in my life,and they both hauled butt on the freeway! Plugs,cap,rotor and timing would be your first cheap fixes.Or carb!{choke issues}