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  #1  
Old 01-19-2002, 07:53 AM
65Belv 65Belv is offline
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Default building imca hobby stock

This is my first atempt at dirt racing, My question is what is a good car for hobby stock, car must have min. wheel base of109. inches, as for the motor would you go with 340 or 360, [chrysler allowed 370] rules state 360 heads only with 2 bbl, must have 76 cc's heads or larger, i plan on running automatic,

Thanks for the help
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  #2  
Old 01-19-2002, 11:24 AM
Rich33 Rich33 is offline
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If I were you I'd be looking for a 109 inch wheelbase two door "A" body. Like a '73 or newer Dart Swinger (notice I didn't say Dart Sport, David D? LOL). Stay away from 4 doors. There's a rule for IMCA hobbies that says the back of your seat can't be behind the "B" pillar. On a 4 door that's pretty far forward.

There's always a chance that tech might over-look something like that (remember, each IMCA sanctioned track may intrepret the rules somewhat differently), but I'd avoid the issue and get a 2 door Dart. These cars are light, the front end is easily adjusted, and aftermarket springs and torsions are readily available to set the car up right.

Run a 360 in the Dart. 340's are getting rare and in this class you could use the extra torque a 360 gives. Don't worry about that 76 cc rule. The rules are written around Chevies. Most 360 heads vary anywhere from 68 to 72 or so cc's. As long as you are 9 to 1 or less on compression, no one's gonna sweat how many cc's your heads are.

Any stock 360 will pass the 9 to 1 rule. Freshen one up with new rings and bearings and then add a MP 284/484 cam. That cam's a really good choice for a hobby stock...Keep in mind that it's really easy to make a mistake and over-cam for this class. Buy a pair of newer Dodge Magnum truck exhaust manifolds. You'll have to raise the engine up 2 inches or so to get them to fit, but they're worth it.

You'll be running against about a billion GM metric cars. But, don't worry: they have their own problems. They have crappy front end geometry that takes a lot of work to fix and the stock 4 link rear suspension ins't all that great if the rules limit what you can do to it. Put your Dart together and pass 'em all on the outside!
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Old 01-19-2002, 07:27 PM
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David D David D is offline
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Well actually.......................................... ........
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Old 01-20-2002, 07:49 AM
65Belv 65Belv is offline
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I know where I can get a 74 Duster, would that be to heavy, also what is a goor gear to run

Thanks
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Old 01-20-2002, 08:21 AM
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David D David D is offline
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Default Sorry Rich, gotta answer(LOL)

The factory wheel bases for A-body Mopars are as follows:

Duster, Demon, Dart Sport, all pre-'74 Valiants except Scamp, 67-69 Barracudas are 108"

Dart Swinger, Dart 2dr sedan, 4 dr sedan, Vailant Scamp, and 74 &newer Valiant 4 dr sedans are 111"

Can you use the Duster? How does IMCA determine wheel base? Factory spec? Measure the actual car? The Dart Sport I built last year measures 109" and some change using Landrum springs with a 20.5" front section. As far as weight, an A-body is about as light as it gets in a Mopar. Again, the the car I did last year was 3098# with a 200# driver and 5 gal of gas. Gearing depends on many things, surface, length of track, max rpm of engine.
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Old 01-20-2002, 06:10 PM
jelsr jelsr is offline
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65Belv,
The Duster will make a great starter car. They are relatively light and have good geometry front and rear. Front is fragile though so avoid contact when possible. Like Rich33 said, the MP284/484 is a good Hobby Stock cam, gives a pretty wide power band. Try to gear for 5200 to 5500 at end of straights. A manual valve body is also a plus for your A/T. Eliminates the throttle valve.
The Duster is 108"WB but with the Landrum rear springs will read 108-1/2". A spacer between the front rear spring hanger and body will get you to the required 109". They vary a little so measure it up and see what you need. The 1.04" or 1.09" torsion bars would be a good start depending on banks. The steeper the bank in the turns the more bar is needed. You'll have a ball!
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Old 01-21-2002, 12:27 PM
Rich33 Rich33 is offline
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You can also get the 109 inch wheel base by mounting two adjustable spring spacer lowering blocks between the leafs and the rear end housing and then cranking them back enough to meet the measurement.

The IMCA hobby stock rules just say 109 inch minimum wheelbase for unibodies. It says nothing about it being per factory spec's. Nevertheless, get that Duster, call it a Dart Sport, and maintain that it has a 109 inch wheelbase from the factory. Heck, most tech guys dont even know that Dodge made a Dart Sport that looks like a Duster, let alone what wheelbase it had.
That wheelbase rule is there to keep Firebirds and Camaros out of the class, so you should be fine.

It's already been mentioned, but in order to help with gearing, you need to tell us the length of the track and banking.
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Old 01-22-2002, 09:55 PM
65Belv 65Belv is offline
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the track I will race at is a 3/8 mile , 28 degree banks. I thnk I found a Swinger, already done, minus motor an tranny.

The rules state stock 2 bbl carb. does it matter if it came off a sb or a bb. It doesm't state so i'm guessing it don't matter.

On the torshen bars can you run 2 different bars. one light an one heavy? or is that a bad idea.


Thanks Mike
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Old 01-22-2002, 10:25 PM
jelsr jelsr is offline
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2 different dia's not recommended due to spring/shock complication fixes not available in hobby stock. The carb question is iffy, Mopars came std with Carter, Holley, Stromberg, Rochester, and others so a valid arguement could be presented for about anything but Motorcraft.
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Old 01-23-2002, 02:56 AM
SUPRDUD SUPRDUD is offline
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This is what I have been wanting to build also but other things have been coming before a race car.................I have talked to Kirk at the IMCA and as long as it measures 109 inches actual is what matters so a Duster or Dart Sport is fine with spacers. You can run a holley from a 360, it's an odd one but is legal. I have 3 if you need one cheap.

What track are you planning to run at?

Best of luck!
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Old 01-23-2002, 07:32 AM
65Belv 65Belv is offline
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I plan on running at Butler County, does anyboby know of any Swingers that are roller? I would be interested in buying one, Just in case other deal does not work out. What part of state are you from?

Mike
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Old 01-24-2002, 02:28 AM
SUPRDUD SUPRDUD is offline
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I live west of Hastings and would run at the Speed Bowl in Red Cloud or at Deshler. Sorry I don't know of any race cars or I would buy them. Not much for Mopars running in lower classes that I have seen, but I don't get to go too often.
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  #13  
Old 01-30-2002, 11:25 AM
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Isnt IMCA going to just 360 ci next year, I wonder where they plan on finding fresh blocks to run in a hobby stock. There is a couple IMCA tracks here and thats what their rules say starting july 1st. The rules also say stock appearing does that mean that you can put a stroked crank in or did I not read into it enough (or to much?)
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  #14  
Old 01-30-2002, 02:09 PM
Rich33 Rich33 is offline
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IMCA's hobby stock rules for 2002 read -

"Stroke must match block. Harmonic balancer may not be altered. Cylinder heads must be unaltered approved OEM. Maximum 360 cubic inches (370 for Chrysler)."

There's no change that I know of from IMCA for the middle of the season. I was on the phone with them yesterday and talked with Bret Root last month. He didn't say anything about doing that.
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