I have an 81-z with a 454 n2o.I am backhalfing the car with chris alston's kit 4 link.My question is I want to put mickey thompson 28x12.5-15.would anyone know how wide my ford 9" should be ? I do not want them protruding outside the wheel well.Before someone asks why the big tires 2 reasons. 1 like the look. 2 got about 800 hp with the n20 want to hook up good.Thanks for any help.

If noone knows how long then does anyone know how to figure it out? I would not want to get the rear shortened the wrong size. Three times I cut the tube three times its still to short.

Try posting your question down in the competiton Camaros section as well...might get a quicker response...

Try posting your question down in the competiton Camaros section as well...might get a quicker response...
Done. ;)

first you will need to figure out your back half chassis ones the floors are cut out you will be able to test fit the tires AND wheels from there you will be able to determine the flange to flang distance because you question can't be answered without knowing what axle bearing flang you want to use or what wheel offset.

Yup. you have to know the tire section width, the wheel backspace, THEN you can start to calculate what you want in a housing width. Also make SURE you know 100% positive the driveshaft offset. It's NOT centered in the car so you can't run the pinion centered between the whee's.

Here's a worksheet from Alstons site to help you understand all that you have to know before you can order / buy a rear housing.

http://www.cachassisworks.com/worksheets/fab9_instructions.pdf

thanks for the help.Next problem someone told me I can not run a backhalfed car at the track does anyone know if this is true or is he scared cause he has a 79 stang running 21.2 quarter and originally said when I started building my car he would beat me all day long. Never happen he has a ford need I say more

sorry 12.2

Don't know what track he runs at but I've been running my backhalved truck in street in the Summit series, and Street in the Truckin Magazine series since 1995 and never heard such a line of BS!

If your serious about the job I would start dropping the rear and cutting out the trunk floor it makes things so much easier to work and mock things up know what size wheels you want to use espeacially the backspacing ,know the height,width of tires make sure they will fit inbetween the wheel wells and have enough room front and back, if your going to fab your own frame rails? if your going to get a complete kit know the width from rail to rail.
put your plan on paper!!!!!
when you know exactly what you want to do and everything makes sense mock things up dont forget tieing in the subframe
you might want to consider a extended 2x3 square tubing from your back half kit straight into the front subframe you might just find that your going to want a taller tire maybe wider

The rear end your looking for is out of a 67-70 mustang or fairlane. Its about 60" wide. if you do a mini tub on the car, you can fit a 31x14 goodyear under it. or a 31x16.5 ET street with a 15x12 wheel with a 7-1/4" BS
i have it done to mine

[QUOTE=junkyarddog134]I am backhalfing the car My question is I want to put mickey thompson 28x12.5-15.would anyone know how wide my ford 9" should be ? QUOTE]
why do you need to backhalf the car for this tire??
is it cause you need the 4 link?
cause I have that tire on my camaro and its rear end is the stock length.
http://thumb10.webshots.net/t/30/466/5/3/44/2903503440053959750FhLlhr_th.jpg (http://rides.webshots.com/photo/2903503440053959750FhLlhr)

my frame rails are shot up front and did research and it makes sense to back half.the rest of the car is perfect.I am going with chris alstons 4 link kit.I would like to run bigger tires but I can not due to true street class.So what you are saying is that I could put these frame rails for the 4 link in the same place as stock and still run that tire. Thanks

the rear end can be several legnths and still work. Im getting ready to do mine and heres how im going about it. I have 15x8 rims currently with 275/60-15 tires that fit nicely under the wheel well lip. The rim back space is 4.5 inches. My measurements are the overall width of the tires at the buldge (71.5 inches). My tire width at the buldge is 11". Now lets look at my wheel back space. My rims are 8" wide and my backspace is 4 and 1/2. so here it is . Overall width 71.5", minus 1/2 tire width plus 1/2 inch of wheel offset. Remember my tires are 11" so half is 5.5" plus the 1/2 wheel offset. There are 2 sides in this factor (drivers and passenger) . So it looks like this
overall width= 70 1/2
minus 1/2 tire width 5 1/2" x 2= 11"
minus wheel offset 1/2" x2=1"
70 1/2 " - 10" = 60 1/2 axle to axle with including drum brakes. My rear end is about 60" wide. Use the same process to determing any tire width and rim offset combo. Dont worry too much about the rim width as long as you can get the section (buldge) width of your desired tire with that particular rim width.

28x12.5-15

Brand: Mickey Thompson
Product Line: Mickey Thompson ET Street Tires
Part Type: Tires
Tire Size: 28.00 x 12.50-15
Rim Diameter (in): 15 in.
Sidewall Style: Blackwall
Tire Construction: Bias-ply
Directional: No
Tire Diameter (in): 28.10 in.
Minimum Recommended Rim Width (in): 9.00 in.
Maximum Recommended Rim Width (in): 11.00 in.
Tread Width (in): 10.00 in.
Section Width (in): 12.60 in
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Brand: Mickey Thompson
Product Line: Mickey Thompson Sportsman Pro Tires
Part Type: Tires
Tire Size: 28.00 x 12.50-15
Rim Diameter (in): 15 in.
Sidewall Style: Blackwall
Tire Construction: Bias-ply
Directional: No
Tire Diameter (in): 28.00 in.
Minimum Recommended Rim Width (in): 8.00 in.
Maximum Recommended Rim Width (in): 11.00 in.
Tread Width (in): 10.40 in.
Section Width (in): 13.10 in.
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I checked and could not find any slicks that size,so I'm guessing that your running either one of these.
I have these on mine,
Mickey Thompson Sportsman Pro Tires
28.00 x 12.50-15

yes mickey thompson sportman pro 28-12.5-15