Craig Chamboullides

I've tried looking up this info and cant find it so I hope someone can help. I bought a ford 9" out of a 3rd gen and I'm putting it in my 4th gen, I know that the rear is about 3" total shorter but not sure what that means for wheel options. Hoping someone may have done the same and knows what back space I would need to run.

TIA

HCI2000SS

iTrader: (2)

A guy on the local Detroit's Craglist was selling a DTS 12 bolt off a 3rd gen, and said it was exactly the same as the 4th gen except about one inch shorter on each side. You would need a certain offset on the wheels for it to work. Sounds like it can be done depending on how much of a difference there ends up being

SteenH

You'll want to measure from wheel mounting surface to wheel mounting surface to figure out exactly how different it is from your 4th gen rear. Aftermarket rears can vary slightly in width (in my limited experience.)
Stock width 4th gen rears usually work well with 7.5 inches of backspacing on a 10" wheel. If it's approximately an inch to inch and a half difference on each side (should be), it's likely a 6.5" bs wheel (10" wide) could work well.
Best of luck

leadfoot4

iTrader: (1)

I owned both a 3rd gen car, as well as a 4th gen. FWIW, although the 3rd gen car came with 15x7" wheels as standard equipment, I ran 15x8" wheels, with 4" backspacing, and the wheels were pretty well "centered" within the wheel wells.

My 4th gen car came with 16x8" wheels, and they had about 6" of backspacing. This would lead be to believe that the 3rd gen rear end is between 1.5 to 2" narrower than a 4th gen unit.

MidwestChassis

iTrader: (5)

A 3rd gen rearend is 1.5'' narrower per-side than a 4th gen so say you where using a 15x10'' with 7.5 backspacing on your stock 4th gen with the narrower rearend you would use a 15x10 with a 6'' backspacing.

Craig Chamboullides

Thanks for the reply guys. Been busy getting this rear in. Sounds like I may be better off with a spacer and longer studs rather than try to find a weird off set.

leadfoot4

iTrader: (1)

I wouldn't call it a "weird offset". I would be tempted to think that a 3rd gen wheel would work just fine, and wheels with THAT offset are plentiful..........

BullyDawg

iTrader: (1)

You can run 3rd gen rear wheels, which will give you wider lips, or you can run a 1.5" spacer on your wheels. You won't need longer studs with them.

fst100

iTrader: (5)

so basically run something like hubcentric spacers to be able to run a 3rd gen (12bolt) rear? is that what I'm understanding?

Craig Chamboullides

I thought the 3rd gen wheel would actually be further in the wheel well. I know several guys run a 6.5 on 3rd gen but have to do a lot of clearance to do so.

Craig Chamboullides

if I were to try a 5.5 would it look like a 70's drag car with half the wheel sticking out?

leadfoot4

iTrader: (1)

It shouldn't.....as I previously mentioned, on my '85 Firebird, I ran 8" rims with a 4" backspacing, with NO issues. Therefore, for example, if you added 2" to the wheels I had, making it a 10" rim, and "split the increase", you'd have 5" in back and 5" in front. Still should work, and with a 5.5" BS, the tires would be inset a tad, compared to what I ran. At that point, the section width of the tires you're using, would most likely be the limiting factor. But you'd definitely need an adjustable PHB, to get the rear axle EXACTLY centered.

codyvette

iTrader: (24)

Many people intentionally narrow the rear end in fourth gen cars 1.5" just so they can run a wide outside lip on there rims and still be tucked under the fender well. That makes them the same width as a third gen car. This also greatly widens the selection of wheels that you can chose from, both new and used.

codyvette

iTrader: (24)

Yes, or get better looking wheels.