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Chassis and suspension Tech discussions for Sportsman Pro/Street Stock


tricknology

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This Topic's goal is to start a disscusion where we can share our ideas on building the Sportsman Pro/Street Stock type chassis using stock type frames and suspensions.

 

Please reply with what has worked at Your track, or on your team.

 

Up North here in the Detroit Area, the Leaf spring Camros are Rare, Old, and Expensive. finding a 30 year old Camaro that is cheap and rust free to build is very hard.

 

And with Scrap metal going for over $250 a ton, you folks down south will soon lose access to these 30 year old cars... ever big Detroit Iron car is going to the crusher for scrap.

 

so many tracks are now allowing the use of the Plentiful and Cheap 1979 to 2001, Ford Crown Victoria chassis to be used with a General MOtors V8 and trans.

 

guys are getting 1998 to 2001 Ford Crown Vics and are installing a Chevy V8 and a Powerglide, and are racing in stock type classes. The tracks are allowing this Mix-match because, the Supply of cheap and plentiful of GM Rear wheel drive V8 cars is GONE...they have all went to the crusher!

 

here are some drawings of a trick ""STOCK "" upper control arm......

 

http://www.p71interceptor.com/suspension/front/moog2061.pdf

 

 

 

Here is are discussions about the 1998 -2002 Crown Vic rear suspension with pictures It looks simular to a Dirt LM Rear suspension 4 parrallel rear contorl arms with Watts linkage track bar system....Very Cool rear suspension! links..

 

http://www.crownvic.net/ubbthreads/ubbthre...ite_id=1#import

 

http://www.crownvic.net/ubbthreads/ubbthre...ite_id=1#import

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a while ago, I received this e-mail question and am posting it along with the responce.....

 

( NOTE IT IS LEGAL at most tracks, including Spartan, Springport, Flat Rock, Kalamazoo, and Dixie, that run sportsmans Pro/Street Stocks, to use a GM Engine In a shortened Ford frame)

 

Arnold, can you tell me if you know what rear end is in a 2003 Crown Vic? Does this rear end have a "pumpkin" like A 9" ford? I was told that this year car has a four link rear end, is this true. Would there be any advantages to using this frame. It also has aluminum upper and lower A arms.

I race at Spartan and am considering building something new.

Thanks for your time.

 

 

Dear Mr. XXXXXXXX,

 

I built many Street Stocks using the 1965 to 1978 full sized Ford Galaxy, LTD, Mercury Marquise. The 1976 to 1978 frames are a little lighter because they went from .110 thick steel to .090 steel.

 

They have a Very Wide track width, about 3 to 4 inches wider than a GM chassis.

 

They come with a Heavy duty Ford 9 inch rear axle.

 

The 1970's Lincoln Town Car disc Brake Rear axle Bolts right in, No mods needed.

 

They come from the factory with a 3 link/panhard bar rear suspension.

 

They have Heavy Duty; spindles, hubs, Wheel bearings, Tie rods, Ball joints, and wheel studs. the spindles are Forged Steel NOT Cast iron, so tabs can be welded on to adapt the GM Calipers if you want to.

 

I built many Street Stocks using the 1976 to 1978 Full sized Ford LTD frame, and at Flat Rock they still run strong, against cars that use the Full HOWE racing suspensions.

 

The frame is Very strong, and is Boxed from the factory. It is very EASY to shorten the wheel base to 105"" because the frame rails are rectangular tubing.

 

But now these OLD frames are getting a very hard to find locally. So most builders will build the newer Ford Chassis.

 

 

In 1979 Ford completely changed their frames and copied the GM front and rear suspensions, the 1979 to 1997 ford Crown Vic, Mercury Marquise, Lincoln Town, car frames are similar to the GM Chassis but are MUCH stronger, but because they came with GM type Angled 4 link rear suspension... And because for 2005 Spartan does not allow you to modify your rear suspension by installing a Simple 3 link rear suspension, They do not make as good a candidate as the 1998 to 2001 Ford Chassis. The 1998 to 2001 Chassis is just like the 1979 to 1997 chassis except it has a much better rear suspension.

 

In 1998, Ford Updated the rear suspension on the Crown vic, Mercury Marquise, Lincoln Town Car chassis, This would make a good candidate..Because..

 

It has the same front suspension as the 1979 and up models, so parts are plentiful and cheap.

 

It has a wide tread width..

 

It has a strong frame, the main frame rails are of 2X4 rectangular tubing. shortening the wheel base from 114.6"" to 105"" is EASY.

 

It has high rear frame kickups that will clear the rear axle when the car is lowered.

 

It has heavy duty, Spindles, hubs, brakes, Ball joints, tie rods, and wheel studs.

 

It has a Strong rear axle, with available rear discs. Many cars came with a 3.55 ratio rear axle. Using a Powerglide Trans will give you 6.25 final ratio.

 

And for 1998, the Rear suspension was completely changed to copy a Dirt Late model, It has a Watts Linkage in combination with Parallel 4 links, This is cool rear suspension.

 

And because this 1998 & up Crown vic, Mercury Marquise, Lincoln Town car, frame was made in LARGE numbers they are locally Available and CHEAP!

 

A 1998 to 2001 frame will not need to be sand blasted, it will be rust free.

 

Most of these cars were owned by Old folks and are Low milage. a chassis with about 50,000 miles can be had for a few hundred dollars, You will not have to rebuild any thing... You will use the original Ball joints, tie rods, wheel bearings, rotors, calipers, control arms, and rear axle.

 

Soo lets look at the costs, work and time to build a Street Stock using the 1998 & newer Ford chassis.

 

shop around get a low milage 1998 & up chassis that has the disc brake 3.55 ratio rear axle.

 

YOU are saved the time, money and work of rebuilding the suspension and sand blasting the frame. You do not have to change the rear axle ratio, it is already OK.

 

shorten the Main 2X4 frame rails to get 105"" wheelbase.

 

Install your roll cage. ( as far to the rear as possible).

 

Install the Fabricated steel interior.

 

Install your Chevy V8 with the powerglide trans.

 

Install your Steel template body.

 

Install your racing springs and shocks.

 

Go racing with a killer car that is LOW cost, easy to build, easy to repair, that handles great as it came from the factory.

 

Note......All the 1979 to 2001 Ford

Crown vic, Mercury Marquise, Lincoln Town Car, Front suspensions are almost identical, They are much like the GM front suspension; An all steel suspension that is Front Steer with a steering box (No Rack and Pinion). In fact many racers install the Crown Vic lower A-arms which on a GM chassis to widen the front track width.

 

But In 2002, Ford Completely changed the FRONT suspension on the Crown Vic, Mercury Marquise, Lincoln Town to an all aluminum SLA suspension with Rack and Pinion steering.

Spartan Does not allow aluminum suspensions.

Therefore, The 2002 and up Crown Vic front suspensions are NOT Legal for Spartan.

 

BUT the 1979 to 2001 Ford Crown vic, Mercury Marquise, Lincoln Town Car, Chassis IS LEGAL.

 

If your Track does NOT allow the addition of a Simple 3 link rear suspension, I would build the 1998 to 2001 Ford Chassis because it has the parallel 4 link rear suspension with a Watts linkage. If for 2006 Spartan allows the addition of a simple 3 link rear suspension then Any 1979 to 2001 Ford chassis will work equally well.

 

All 1979 and up Fords come with a 8.8 "" Ring gear rear axle, and it is much like the GM rear end, and does not have a removable pumpkin type center section like the Ford 9'' ring gear rear axle does. But Motive Gear makes many gear ratios for this rear axle.

 

Click on

 

http://www.motivegear.com/

 

 

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Shortening the Ford main frame rails to get a shorter wheelbase.....

 

I have always shortened the Ford frames at the rear where the rear clip attaches to the Main frame rails, Yes you can do it at the front also, but then you lose the 1'' dia. referance holes at the front of the main frame rails. I use these front main frame rail holes as datum points when I have to install a new front clip after a wreck.

 

Heres how you shorten a Ford Frame...

 

level the frame using many supports.

 

weld in a 1 1/2 x 1 1/2 rear cross member to the rear clip where it attaches to the Main frame rails, use the 1 "" holes in the frame rails or the rear control arm mounting holes as datum points. INstall this cross member level to the bottom of the frame and perpendicular to the main frame rails.

 

the Old ford frames have a 121"" wB and the NEW Ford frames have a 114 to 115'' wb (114.6) .

 

so lets say you are using the New 1998-2001 frame, 115 minus 108 = 7 inches that the Main frame rails need to be shortened.

 

NEXT install front cross member so that it is forward of the rear cross member by 2 feet plus the amount you need to shorten the frame rails..( 24 + 7 = 31).

Make it level to the bottom of the frame rails and parrallel the rear crossmember . This front cross member will be attached to the main frame rails and is 31 "" forward of the rear crossmember that is attched to the rear clip. ( inside to inside demensions).

 

Now befor you cut the frame apart, make a level line in the rear clip with a marker, so that when you reattach the rear clip you will have a level mark as a refferance, and the rear cilp will be reattached with the level mark in the level position.

 

NOw you can use a torch and scarf off the factory welds away where the rear clip attaches to the main frame rails. Do Not cut into the Main Frame rails, only scraf away the outside of the weld.

 

slide the rear clip back, which pulls out the intact main frame rails out of the rear cilp pocket.

 

Shorten the rear end of the 2 X 4 main frame rails 7 "".

 

Using 2 carpenters squares as No-Go gauges between the 1 1/2 "" cross members, slide the rear clip forward, (putting the shortened main frame rails into ther rear cllip pocket) untill the distance betweent the cross members is 2 foot. use the Carpenters squares as no-go gauges between the crossmembers to get your 2 foot distance.

 

Support the rear clip to get it level with your level line marked on the rear clip.

 

Tack weld the rear cilp the the main frame rails.

 

using the 1 inch hole in the main frame rails as datum points REMEASURE EVERYTHING.

 

Finish weld the rear clip to the main frame rails.

 

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Here is a lot of INFORMATION on the Ford Crown Vic frames and suspensions!!!

 

when building a new car USE this chasssis!!!

 

Main page....

 

http://www.p71interceptor.com/

 

Lots Front suspension Info AND PICTURES of the Crown Vic Suspension Scroll to the bottom of this link...the crown vic uses COOL/Trick upper a-arms....

 

http://www.p71interceptor.com/suspension/front/index.html

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