New to Forum. Help with Suspension/Wheel Sizing Sizing.

[302J-Code]

Hello Everyone,

Im new to the Site, so Please help a me out

Im 20 years old, I sold my 71 Camaro 468 cid 4spd to buy a 1968 mustang Fastback J-Code 302/ toploader 4spd, Highlander Green. Ford 9" 3.25 conventional. Currently in the process of restoring it slowly due to money but saved enough to start the suspension and get me some new wheels. .

Currently what I decided to do with the Suspension.

Front: Complete New Front Suspension kit (New upper and lower arms w/ new hardware) Shelby Drop, 620 Coil Springs, Front 1 1/8" Sway Bar, Doetsch Tech Adjustable Front Shocks, Also hopefully in the near future Ill find some front disc Brakes off a 2000-04 mustang cobra mach 1 and use the mustang steve disc brake conversion kit.

Rear: Keep 3.25 gears for now. 5 Mid-eye Lead Springs, Rear 3/4" Sway Bar,Doetsch Tech Adjustable Front Shocks, And also again hopefully in the near future Ill find some Rear disc Brakes off a 2000-04 mustang cobra mach 1 and use the mustang steve disc brake conversion kit. Also sometime in the future Competition Engineering Slide-A-Link Traction Bars, Maier Racing Subframe Connectors.

Now for the Wheels/Tires.

Tires: Probable BFgoodrich Radial T/A KDW 2 Tires.
American Racing Rims

Front: 17x8 with 4.75 Backspacing 235/45/17

Rear: 17x9.5 with 5.75 Backspacing 275/40/17

Im Building the car to drive at least 3-4 times a week during good weather. Possibly some Track time in the future. Also Occasional freeway driving.

I have read many threads about mustangs running a similar set up. I just would like to be absolutely positive before spending the money lol

Now for my Questions lol

1) With all the new suspension put on and new wheels, Will the car sit Level or be Higher in the back? -I just don't want the rear to be lower then the front.

2) Do I have the Correct Backspacing for my Wheels?

3) With it being lowered by the shelby drop and 620 Coil Springs and having disc brakes in front will I experience any Rubbing issues with my front Wheel and Tire Size?

4) Also in the Back being lowered by Mid-Eye Leaf Springs and also having Rear Disc Brakes will I have any rubbing Issues?

5) Can I get away with 285/40/17 Tires in the Back with Rolled Fenders?

If I have to Roll all 4 Sides I will.

Also a Side Note There will be Subs in the back in a Custom Box, And will also have passengers in the backseat occasional. This may be a factor on rubbing issues that may come up.

At 20 years old, Im aiming for the Widest possible tires tucked in the back without having any major rubbing issues. I will take the car to the track in the future as well.

Thank you. I appreciate any opinions or information that you can throw my way.

[Boom]

I think 8" wide you have to watch the ball joint for clearance, I am looking at wheels so I'll be keeping an eye on this thread.

I know that 5 leaf springs will be pretty stiff, might try a 4.5 if you plan to drive this alot.

[302J-Code]

Originally Posted by Boom

I think 8" wide you have to watch the ball joint for clearance, I am looking at wheels so I'll be keeping an eye on this thread.

I know that 5 leaf springs will be pretty stiff, might try a 4.5 if you plan to drive this alot.

Ill look into the ball joint clearance. Thats a good point. Also yes I have heard 5 leaf springs are pretty stiff i may get 4.5 if they are too stiff. Depending on what other people say. Thank you One of these days I wanna take the 6 hour drive down south towards Los Angels CA.

[bartl]

My $0.02 from an "Old Fart"...

Originally Posted by 302J-Code

Hello Everyone,

Im new to the Site, so Please help a me out

Im 20 years old, I sold my 71 Camaro 468 cid 4spd to buy a 1968 mustang Fastback J-Code 302/ toploader 4spd, Highlander Green. Ford 9" 3.25 conventional. Currently in the process of restoring it slowly due to money but saved enough to start the suspension and get me some new wheels. .

Currently what I decided to do with the Suspension.

Front: Complete New Front Suspension kit (New upper and lower arms w/ new hardware) Shelby Drop, 620 Coil Springs, Front 1 1/8" Sway Bar, Doetsch Tech Adjustable Front Shocks, Also hopefully in the near future Ill find some front disc Brakes off a 2000-04 mustang cobra mach 1 and use the mustang steve disc brake conversion kit.

Sounds decent. Consider rollerizing the control arm shafts and lower spring mount as well as adding a hinged adjustable strut rod. Don't forget chassis stiffness. With the contact patch you're putting on the ground subframe connectors, export brace and monte carlo bar are a must.If you stick with an OE-type UCA/LCA, consider boxing them for torsional rigidity. You didn't say what you were planning on doing for steering so I assume you'll be sticking with a 16:1 stock box with no assist? Think about the Shelby Quick Steer Pitman and Idler arms.

Rear: Keep 3.25 gears for now. 5 Mid-eye Lead Springs, Rear 3/4" Sway Bar,Doetsch Tech Adjustable Front Shocks, And also again hopefully in the near future Ill find some Rear disc Brakes off a 2000-04 mustang cobra mach 1 and use the mustang steve disc brake conversion kit. Also sometime in the future Competition Engineering Slide-A-Link Traction Bars, Maier Racing Subframe Connectors.

Also sounds mostly good. Ditch the rear sway bar, you won't need it, but consider an adjustable panhard or watts instead. I'd use the overrider-style traction bar myself, especially for a road car. 3.25's are fine for mixed driving, 3.50's will help from the hole but you'll give up some fuel mileage on the divided highways.

Now for the Wheels/Tires.

Tires: Probable BFgoodrich Radial T/A KDW 2 Tires.
American Racing Rims

Front: 17x8 with 4.75 Backspacing 235/45/17

+1 on the other posters comment about rim width. A tubular UCA with negative wedge may give you the clearance you need.

Rear: 17x9.5 with 5.75 Backspacing 275/40/17

Really don't think you need anything over 8 inches and a 245 on the rear. You want to remember that you don't want the rear quite as sticky as the front.

Im Building the car to drive at least 3-4 times a week during good weather. Possibly some Track time in the future. Also Occasional freeway driving.

I have read many threads about mustangs running a similar set up. I just would like to be absolutely positive before spending the money lol

Now for my Questions lol

1) With all the new suspension put on and new wheels, Will the car sit Level or be Higher in the back? -I just don't want the rear to be lower then the front.

With 5 leaf mids you'll probably sit a tad higher in the back. If you're going to do any serious track time you might want to check in to reverse eyes. See if you can find anybody local running a similar combo first.

2) Do I have the Correct Backspacing for my Wheels?

Check out Dodgestangs Tire & Wheel Fitment Chart off the main page.

3) With it being lowered by the shelby drop and 620 Coil Springs and having disc brakes in front will I experience any Rubbing issues with my front Wheel and Tire Size?

The "Shelby" or Arning Drop doesn't really drop the front end all that much, maybe 1/2" tops but, more importantly, lowers the pickup point of the UCA to allow more camber gain under compression. Disc brakes should not affect your track width. Starting with stock length springs will allow you to let them settle and then trim a portion from the upper end to obtain the optimum height.

4) Also in the Back being lowered by Mid-Eye Leaf Springs and also having Rear Disc Brakes will I have any rubbing Issues?

Again, the discs will not change the rear track. Tire width and backspacing will be the determining factors here. The goal is to keep the tire inside the lip, whether it's rolled or not. Under compression in hard turns or positive G it won't matter much what springs you have as the tire and wheel will be getting stuffed into the wheelwell. You don't want to have to raise the rear end for tire clearance as that will raise the roll center. You can force it back down some with the panhard bar but that would be counterproductive.

5) Can I get away with 285/40/17 Tires in the Back with Rolled Fenders?

If you REALLY want the big stickies front and rear you may want to think "mini-tubs" 'cause I think you're going to be very close due to the radius of the inner wheelhouse.

If I have to Roll all 4 Sides I will.

Also a Side Note There will be Subs in the back in a Custom Box, And will also have passengers in the backseat occasional.

Having ridden in the back of a '67 Fastback (when I was 13) all I can say is "you must have tiny friends or not like them very much"> :-)

This may be a factor on rubbing issues that may come up.

At 20 years old, Im aiming for the Widest possible tires tucked in the back without having any major rubbing issues. I will take the car to the track in the future as well.

Thank you. I appreciate any opinions or information that you can throw my way.

[302J-Code]

Originally Posted by bartl

My $0.02 from an "Old Fart"...

Hey bartl,

First off just wanted to say I appreciate the the information and the time you spent writing it.

Well you gave plenty of information and your opinion thanks. Im not to familiar with some of the things you said due to the fact Im young and still learning. .

Phrases not too familiar with:
-Rollerizing the control arm Shafts and lower spring mount. (I plan to buy roller spring perches) maybe from open tracker.

-Hinged adjustable strut rod kit (good point will look into getting a kit)

-For chassis Stiffness I forgot to mention I have already bought an export brace and monte carlo bar. Soon in in time will be getting subframe connectors for sure.

-Yes for now I will be buying New OE-type LCA/UCA.
What do you mean by "Boxing them for torsional rigidity"?

-For steering I have the stock Power steering unit.
I looked into a shelby quick steering pitman and idler arm and only found them for 65/66 mustangs any suggestions

-Im leaning towards Fays2 Watts system over a panhard. very pricey thought around $650 probable will invest in something like that in the future. Full time college student money is tight lol

-I actually heard that override-style traction bars are better then under-ride bars. Problem is I couldn't find any for a 68 mustang. Any suggestions?

-Ill keep in mind about keeping 8" in the back.

-Not too much track time but it ill see the track eventually. What is you opinion on the stiffness of 5 leaf springs compared to 4 1/2?

-I just went out and looked at my car just noticed It already has the 1" shelby drop

-No mini tubs for me Id rather put smaller tires in back

-Rarely but occasional my little brother and sister will be in the back lol

Thanks for everything in advance.

[302J-Code]

Anyone Else have any suggestions or information?
Thanks

[bartl]

Originally Posted by 302J-Code

Hey bartl,

First off just wanted to say I appreciate the the information and the time you spent writing it.

You're very welcome. It's called "paying it forward". Someone helped me a long, long time ago.

Well you gave plenty of information and your opinion thanks. Im not to familiar with some of the things you said due to the fact Im young and still learning. .

Phrases not too familiar with:
-Rollerizing the control arm Shafts and lower spring mount. (I plan to buy roller spring perches) maybe from open tracker.

You can retrofit the control arm mounting to use a spherical roller bearing instead of a steel bushing bonded to an elastomer. It makes it move easier, prevents lateral movement of the arm, and is easier to keep lubricated.

-Hinged adjustable strut rod kit (good point will look into getting a kit)

Either DIY or an adjustable strut rod kit from StreetorTrack or the like. They can use heim joints or a simple swivel at the front to prevent the strut rod from binding at the factory bushing location.

-For chassis Stiffness I forgot to mention I have already bought an export brace and monte carlo bar. Soon in in time will be getting subframe connectors for sure.

Good deal.

-Yes for now I will be buying New OE-type LCA/UCA.
What do you mean by "Boxing them for torsional rigidity"?

If you are using the factory-type upper and lower control arms, which were made from sheet metal stamped using a die, you can reinforce them to prevent twisting and bending by welding a "cover" of sorts on the underside. Some of the Mustang vendors offer a kit to do this, or if you have access to a plasma cutter you can cut your own.

-For steering I have the stock Power steering unit.
I looked into a shelby quick steering pitman and idler arm and only found them for 65/66 mustangs any suggestions

Good question. I suppose that may have something to do with the change in sector shaft size from '66 to '67. I don't know if the geometry is similar between the years but it's possible it may be the same. If it is, you could always have your steering box rebuilt with the small sector shaft and use the '65-66 version, but that would take some research or the knowing brains of guys like 22GT or Chockostang.

-Im leaning towards Fays2 Watts system over a panhard. very pricey thought around $650 probable will invest in something like that in the future. Full time college student money is tight lol

For a mostly street-driven car the panhard rod should be more than satisfactory. Watts are nice, but you have to worry about where your exhaust is going to exit as there may not be enough room to snake it through after installation.

-I actually heard that override-style traction bars are better then under-ride bars. Problem is I couldn't find any for a 68 mustang. Any suggestions?

You could fabricate them yourself, or try THESE GUYS.

-Ill keep in mind about keeping 8" in the back.

Thought you had a 9 inch? If not, I'd definitely think about an 8.8 swap for the ease of rear disc brakes...

-Not too much track time but it ill see the track eventually. What is you opinion on the stiffness of 5 leaf springs compared to 4 1/2?

I have 5 leaf standard eyes and they are stiff, but I didn't buy an LTD, I bough a Mustang.

-I just went out and looked at my car just noticed It already has the 1" shelby drop

Bonus

-No mini tubs for me Id rather put smaller tires in back

I agree wholeheartedly.

-Rarely but occasional my little brother and sister will be in the back lol

Thanks for everything in advance.

Glad to be of service.

[302J-Code]

Originally Posted by bartl

Glad to be of service.

Thanks again for all your information and Knowledge it is very appreciated!