Slicks at the back

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Higgins56

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1971 Mach 1 Fastback now with 503 CID 4 bolt block with AFR Bullit heads , Edelbrock Performer RPM AirGap intake and ProSystems carburettor 1050.
4 sp Toploader with 9" Wavetrac rear.
Caltracs and shocks at the rear.
1" spacers, Plus 400hp & bb torque, manual, drag slicks... Are you using pro spacer style spacers which are bolted in or are you running 3" studs? I am not feeling comfortable with the spacers, slicks and strip combination. Might work and can also rip the studs out of aluminum spacer.

Driveshaft safetyloops can be welded from a round profile pipe and have them welded between the front frames and same to rear depends too how the frames are connected. Friend of mine did similar setup from chromemoly to his '73 Mach1 and it came pretty good. He lives at Ylojarvi I can arrange you a garage visit if you want to.
Your message really woke me up this morning ;)

I had to call one friend running a Ford Futura 1/4 mile in 11 second times since many years.

He told me that actually he has one inch spacers in his car and he had no complaints / fear of using them providing that you assemble them good...

Anyway there must be all kind of spacers available and in youtube you can find scary stories of ripped off wheels etc. The main thing causing these always seem to have been a poor assembly.

Funny - but Eibach for example provides spacers to be used in Porsches as well.

One thing I fully agree with everybody is that if you can run without spacers is a better thing.

Regarding running strips versus racing with spacers I think drag racing does not load the studs that much than cornering all the time on a race track ?

 

Higgins56

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1971 Mach 1 Fastback now with 503 CID 4 bolt block with AFR Bullit heads , Edelbrock Performer RPM AirGap intake and ProSystems carburettor 1050.
4 sp Toploader with 9" Wavetrac rear.
Caltracs and shocks at the rear.
on a 9" rim you will probably need 5.25 back spacing. My current rear tires are 28.5 inches tall and just a bit wider than what you are considering. At the front of the wheel well I had to cut and move the inner fenderwell to make room for my tires to fit.

I would definitely recommend you do some sort of mock up before buying rims and tires that size.
Hi,

I took some photos on the garage floor - hope you can see something....

There is the word " DIF" in the front housing - I could see...

The axle end seems to be 31 splines.

I measured the ratio and it is something like 3.5...

Regarding the Eibach spacers - I measured the axle hub studs ( coming out of the brake drum centre) and they are 23 mm. The spacer is 25 mm. Should be no problem to have the studs/nuts nicely within the spacer housing to get good contact on the spacer/ wheel centers which is most important.

I made some measurements while waiting the spacers to come and the wheel with the 28/ 10.5 tyre sits nicely inside the rear fender on the jacks having space 1" at the front and 2" at the back.

The moment of truth is when I get the car standing on its slick tyres.

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I be4lieve that is a 9 3/8 or sometimes called a 9 1/2 unit.


You can see one in this video clip. As I understand, they use larger bearings and may be noticeably stronger than a 9", but parts are hard to find. On the plus side a 9" carrier will drop into the housing if you ever need to replace it.

 

Finmach

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Do the first mock up without spacer. Just check how it sits, if it contacts the inner wheel well then don't install the stud bolts.

Eibach is one the best manufacturers for the spacers. But, all the sanctioning bodies does not allow to use wheel spacers f.ex. NHRA. Now wonder why? Because the might broke and then it's a possible problem.

Paint the spacers black from the parts you can see them so probably no one will not notice it f.ex. On a drag strip day.

 

Higgins56

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My Car
1971 Mach 1 Fastback now with 503 CID 4 bolt block with AFR Bullit heads , Edelbrock Performer RPM AirGap intake and ProSystems carburettor 1050.
4 sp Toploader with 9" Wavetrac rear.
Caltracs and shocks at the rear.
Do the first mock up without spacer. Just check how it sits, if it contacts the inner wheel well then don't install the stud bolts.

Eibach is one the best manufacturers for the spacers. But, all the sanctioning bodies does not allow to use wheel spacers f.ex. NHRA. Now wonder why? Because the might broke and then it's a possible problem.

Paint the spacers black from the parts you can see them so probably no one will not notice it f.ex. On a drag strip day.
well... I wanted to check this and found some material . NHRA actually allows the use of spacers and advises the fixing of the studs to be done in a certain way as described by a comment below:

"Nevs is correct, the NHRA rule book is worded so that the minimum acceptable amount the stud has to engage the hex portion of the lug (the strongest part of the lug) is an amount equal to the stud's diameter.

Pic from the NHRA rule book attached.

True, engaging ALL the lug threads (and the stud hanging past the lug body) is better, but it's not required to be legal. The minimum requirement is what the diagram shows. "



Do the first mock up without spacer. Just check how it sits, if it contacts the inner wheel well then don't install the stud bolts.

Eibach is one the best manufacturers for the spacers. But, all the sanctioning bodies does not allow to use wheel spacers f.ex. NHRA. Now wonder why? Because the might broke and then it's a possible problem.

Paint the spacers black from the parts you can see them so probably no one will not notice it f.ex. On a drag strip day.
well... I wanted to check this and found some material . NHRA actually allows the use of spacers and advises the fixing of the studs to be done in a certain way as described by a comment below:

"Nevs is correct, the NHRA rule book is worded so that the minimum acceptable amount the stud has to engage the hex portion of the lug (the strongest part of the lug) is an amount equal to the stud's diameter.

Pic from the NHRA rule book attached.

True, engaging ALL the lug threads (and the stud hanging past the lug body) is better, but it's not required to be legal. The minimum requirement is what the diagram shows. "
... and here the text also MENTIONING the wheel spacer.

Screen Shot 2016-04-14 at 10.30.01 PM.png

Screen Shot 2016-04-14 at 10.47.58 PM.png

 
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Finmach

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I'll be damned. I checked the rulebook NHRA and national Finnish Hot Rod Association's (FHRA) rulebook - uses the same picture as above. Spacers are allowed. But, they do not mention a word from spacers like prospacer which are bolted on. Rulebook only states the text above that the studs needs to be long enough.

Obviously they are allowed too since they are not banned?? On road racing circuit I've seen as the prospacer does not hold the wheel attached. But that is a whole different motorsports.

Intresting for sure. Ford Fairmont guy you mentioned above has been on 11.002s on quarter and it's been beaten to "death" for many years. If there are spacers in that car, gosh they are GOOD spacers. I have driven the car 160mph in the past, it surely is capable of doing low 11s on quarter and 166 mph on standing mile, its funny car (it only needs a bigger engine - owner is planning a 427w with P-38 heads from Kaase).

Have you mocked up the wheels/tires yet?


I am not able to modify my last message, but I need to make a correction.

Ford Fairmont guy is not beaten to death many years but his car has been beaten!! :whistling:

 
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Higgins56

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My Car
1971 Mach 1 Fastback now with 503 CID 4 bolt block with AFR Bullit heads , Edelbrock Performer RPM AirGap intake and ProSystems carburettor 1050.
4 sp Toploader with 9" Wavetrac rear.
Caltracs and shocks at the rear.
I'll be damned. I checked the rulebook NHRA and national Finnish Hot Rod Association's (FHRA) rulebook - uses the same picture as above. Spacers are allowed. But, they do not mention a word from spacers like prospacer which are bolted on. Rulebook only states the text above that the studs needs to be long enough.

Obviously they are allowed too since they are not banned?? On road racing circuit I've seen as the prospacer does not hold the wheel attached. But that is a whole different motorsports.

Intresting for sure. Ford Fairmont guy you mentioned above has been on 11.002s on quarter and it's been beaten to "death" for many years. If there are spacers in that car, gosh they are GOOD spacers. I have driven the car 160mph in the past, it surely is capable of doing low 11s on quarter and 166 mph on standing mile, its funny car (it only needs a bigger engine - owner is planning a 427w with P-38 heads from Kaase).

Have you mocked up the wheels/tires yet?


I am not able to modify my last message, but I need to make a correction.

Ford Fairmont guy is not beaten to death many years but his car has been beaten!! :whistling:
As I bought the spacers already I will now wait to get them and fit them in place and lower the car on wheels...

If not succesful - then there are new wheels and spacers available - I hope not ;) !

 

Higgins56

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Location
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My Car
1971 Mach 1 Fastback now with 503 CID 4 bolt block with AFR Bullit heads , Edelbrock Performer RPM AirGap intake and ProSystems carburettor 1050.
4 sp Toploader with 9" Wavetrac rear.
Caltracs and shocks at the rear.
I'll be damned. I checked the rulebook NHRA and national Finnish Hot Rod Association's (FHRA) rulebook - uses the same picture as above. Spacers are allowed. But, they do not mention a word from spacers like prospacer which are bolted on. Rulebook only states the text above that the studs needs to be long enough.

Obviously they are allowed too since they are not banned?? On road racing circuit I've seen as the prospacer does not hold the wheel attached. But that is a whole different motorsports.

Intresting for sure. Ford Fairmont guy you mentioned above has been on 11.002s on quarter and it's been beaten to "death" for many years. If there are spacers in that car, gosh they are GOOD spacers. I have driven the car 160mph in the past, it surely is capable of doing low 11s on quarter and 166 mph on standing mile, its funny car (it only needs a bigger engine - owner is planning a 427w with P-38 heads from Kaase).

Have you mocked up the wheels/tires yet?


I am not able to modify my last message, but I need to make a correction.

Ford Fairmont guy is not beaten to death many years but his car has been beaten!! :whistling:
As I bought the spacers already I will now wait to get them and fit them in place and lower the car on wheels...

If not succesful - then there are new wheels and spacers available - I hope not ;) !
Hi again,

I just got the pro spacers and they fit nicely. Thew original studs leave 1 mm space between the spacer and the wheel hub which is enough. Important is that they shall not protrude over the spacer line.

With these tyrwas you have to hammer the front part of the wheel well a bit and the question is - how much clearance is needed between the tyre and any body structure ?

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If that is your fuel line in the picture, you need to relocate it for safety purposes.

Between the tire and the inside of the fenderwell, you should have a 1/2" or more as the axle will shift side to side slightly. Between the outer tire and wheel well lip, I like a similar amount of space.

You also have to allow for suspension travel as while the tire may clear sitting still, when you romp on it or hit a dip in the road and compress the suspension, it will contact the front edge of the wheel lip.

I widened my wheel tubs on the inside front, it took a day but wasn't difficult. Just rip the wheel well from appx 1/3 of the way up and then make a 90 degree cut to the inside to free it up and then upward to allow the metal to move and overlap about 2/3 the length of the first cut. Push it in flat against the frame rails, weld in a pie shaped filler piece and weld up the lower cut and inner put that now is overlapped. Seam seal everything and undercoat it and reassemble your interior. If you are careful you won't even lose your rear seat belt mounts, but I did on the driver side.

osd4w0.jpg


ig9js2.jpg


 

Higgins56

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My Car
1971 Mach 1 Fastback now with 503 CID 4 bolt block with AFR Bullit heads , Edelbrock Performer RPM AirGap intake and ProSystems carburettor 1050.
4 sp Toploader with 9" Wavetrac rear.
Caltracs and shocks at the rear.
If that is your fuel line in the picture, you need to relocate it for safety purposes.

Between the tire and the inside of the fenderwell, you should have a 1/2" or more as the axle will shift side to side slightly. Between the outer tire and wheel well lip, I like a similar amount of space.

You also have to allow for suspension travel as while the tire may clear sitting still, when you romp on it or hit a dip in the road and compress the suspension, it will contact the front edge of the wheel lip.

I widened my wheel tubs on the inside front, it took a day but wasn't difficult. Just rip the wheel well from appx 1/3 of the way up and then make a 90 degree cut to the inside to free it up and then upward to allow the metal to move and overlap about 2/3 the length of the first cut. Push it in flat against the frame rails, weld in a pie shaped filler piece and weld up the lower cut and inner put that now is overlapped. Seam seal everything and undercoat it and reassemble your interior. If you are careful you won't even lose your rear seat belt mounts, but I did on the driver side.

osd4w0.jpg


ig9js2.jpg
Thanks a lot of your comment Jeff !

Yes - i thought as well that I need to move the fuel line a bit .

The photo is on the driver's side and the clearance is ab. 1/2 inch.

On the other side it is nearly an inch but I think when I move the fuel line I can hammer also the drivers side more to get the inch also on that side - we will see.

By the way I already tried the slicks the first time to accelerate the car - there was no slip at all - the grip was tremendous compared to the Cooper Cobras !!!!

It seems that I need 200 hp more - or a new clutch :)

 
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