70 Barracuda. 295 on 18x10 w/5.5" b.s. & 275 on 18x9 w/5" b.s.

[waskier]

70 Barracuda 383 car.  Hotchkis front end with QA1 K.  13" maybe 14" rotors up front.  12" rotors out back.  With the 14" rotors I'll need 18" wheels.  SO.  Foose 18" F223 Challenger Rallye wheels. 18x10 w/5.5" b.s. with 295/35/18's out back.   18x9 w/5" b.s. with 275/35/18's out front.   DrDiff 1" offset on stock 70 8.75" rear end.   What does everyone think of this? 

[crash340]

That rear combo works great on a Cuda with a B body diff which is approx 3/4" narrower on both sides, no fender trimming needed, you 'may' need to trim the fenders on yours pending the side wall bulge and ride height. I cant comment about the front sorry

[waskier]

so with a stock e body rear axle, should I change the offset?

[72bluNblu]

The fronts will depend on how much track width your aftermarket brake kit adds. I run 275/40/17's on 17x9's with a 5" backspace on my challenger in the front, but that's with 11.75" Mopar disks. They fit, but there isn't a lot of extra space especially on the outside. Most aftermarket brake kits widen the track, and with a 9" rim and a 5" backspace you don't have any extra room for a wider track. For example, I run dr diff's 13" brake kit on my Duster. Great kit, but it adds about 5/16" to the track width on each side. In your case that would mean you'd need 5-5/16" backspace on the front instead of just 5" to clear the fenders.

In the back with an E body rear axle I think you'd want a little more backspace as well. I run a 1" offset on my Challenger in the back as well, but with a 68-70 B body 8 3/4. I have the same 275/40/17s on 17x9s with a 5" backspace and with the B body rear axle they're almost perfectly centered with almost an inch and a half of clearance on each side. With the 1" offset there's plenty of space for 295's, but with the e body axle I think you'd be pretty tight on the quarters with a 10" , zero offset rim and 295's. You lose 3/4" with the E body rear axle, and then another 10mm on the outside with the 295's. So let's call that 1.25", which won't leave you enough clearance to keep from rubbing. Plus you have the same deal with the rear disks, they usually add a 1/4" or so to the track on each side because of the thickness of the rotors.

I'd be looking for at least another 1/4" of backspace in the front and a good 3/4" more in the back. And remember, it's a lot easier to add a thin spacer if you have too much backspace than it is to move the fenders or quarters if you don't.

[WildJones]

DISCLAIMER: These cars have a wide level of tolerances and what works on one car may not necessarily work on another.

On my car I run 18x10s with 295/35/18 front and rear. I haven't actually driven the car, nor have I set up the final alignment, but its been sitting on the wheels for the past 3 or 4 months and the springs have settled in to ride height with zero rubbing. My final alignment specs will only make them tuck in nicer. I'm hoping to achieve neutral handling by running a square setup, plus I can rotate the tires for more even wear. 295s up front are a TIGHT fit, you really need to plan and double check your measurements. The front fenders have about 19" of space from the inner fender to the lip of the fender. I did NOT roll the lips of my fenders in order to fit that wheel and tire combo on either the front or rear of my car.

I'd recommend perusing through the wheels and tire thread to get an idea of what people are running with what sizes and offsets/backspacing. There are plenty of websites that convert backspacing to offset and vice versa to save you some time and some of your sanity. I've also included a link to Will They Fit with a comparison of my setup to your proposed F223 Challenger Ralleye wheels to get an idea of the fit with those vs mine.

http://www.willtheyfit.com/wheels/#.WJ7Bu2GmPaM.link

Front setup: Hotchkis TVS, FirmFeel 1.18 TBs, Ridetech adjustable shocks (about an inch shorter than stock replacements to accommodate my lower ride height), and DrDiff Stage 4 brake kit (these push the wheels out about 3/4" per side over stock if memory serves me correctly).

Rear: RMS Street Lynx with a stock width E body axle housing. DrDiff 11.7 rear disc brakes.

If you're looking to run a more modern looking wheel, then the stock width e body rear end will serve you better than a shorter axle housing. Modern wheels typically have much more backspacing than "classic" style wheels. With my setup, wheels made to fit 94-04 Mustangs were just about a perfect fit.

These are the wheels that I ended up with: http://www.americanmuscle.com/black-amr-18x10-9404.html
I'm not too pleased with how shiny they are with the rest of the car, but I haven't washed the car in probably 4 or 5 years, so I am hoping they match the color and paint when all is said and done. If not, I think they would look way better with a less shiny finish.

This is probably the best shot to give you an idea of ride height and the look from the side:


From the front. Fender clearance looks good both front and rear. Sits in the wheel well pretty well.


To give you an idea of what a 295 looks like out back


It's pretty late at night, but I figured I would pop in and hopefully add some info to what 72blunblu posted. Hopefully this is semi well laid out and makes some sense. Let me know if you need any more info.

[72bluNblu]

DISCLAIMER: These cars have a wide level of tolerances and what works on one car may not necessarily work on another.

On my car I run 18x10s with 295/35/18 front and rear. I haven't actually driven the car, nor have I set up the final alignment, but its been sitting on the wheels for the past 3 or 4 months and the springs have settled in to ride height with zero rubbing. My final alignment specs will only make them tuck in nicer. I'm hoping to achieve neutral handling by running a square setup, plus I can rotate the tires for more even wear. 295s up front are a TIGHT fit, you really need to plan and double check your measurements. The front fenders have about 19" of space from the inner fender to the lip of the fender. I did NOT roll the lips of my fenders in order to fit that wheel and tire combo on either the front or rear of my car.

I'd recommend perusing through the wheels and tire thread to get an idea of what people are running with what sizes and offsets/backspacing. There are plenty of websites that convert backspacing to offset and vice versa to save you some time and some of your sanity. I've also included a link to Will They Fit with a comparison of my setup to your proposed F223 Challenger Ralleye wheels to get an idea of the fit with those vs mine.

http://www.willtheyfit.com/wheels/#.WJ7Bu2GmPaM.link

Front setup: Hotchkis TVS, FirmFeel 1.18 TBs, Ridetech adjustable shocks (about an inch shorter than stock replacements to accommodate my lower ride height), and DrDiff Stage 4 brake kit (these push the wheels out about 3/4" per side over stock if memory serves me correctly).

Rear: RMS Street Lynx with a stock width E body axle housing. DrDiff 11.7 rear disc brakes.

If you're looking to run a more modern looking wheel, then the stock width e body rear end will serve you better than a shorter axle housing. Modern wheels typically have much more backspacing than "classic" style wheels. With my setup, wheels made to fit 94-04 Mustangs were just about a perfect fit.

These are the wheels that I ended up with: http://www.americanmuscle.com/black-amr-18x10-9404.html
I'm not too pleased with how shiny they are with the rest of the car, but I haven't washed the car in probably 4 or 5 years, so I am hoping they match the color and paint when all is said and done. If not, I think they would look way better with a less shiny finish.

It's pretty late at night, but I figured I would pop in and hopefully add some info to what 72blunblu posted. Hopefully this is semi well laid out and makes some sense. Let me know if you need any more info.

Hmmm.

The 18x10's you've got have a 6.3" backspace. In the back that makes perfect sense. A 18x10 with 0 offset has 5.5" of backspace, so that would be centered compared my 17x9's with 5" of backspace and 0 offset. The E-body rear axle is exactly .75" wider on each side compared to the 68-70 B body rear axle I run, so adjusting for the E-body axle would put you at a 6.25" backspace to keep the 18x10's centered with the wider axle. That puts the AMR rims with  6.3" right on target for being centered in the wheel tub, and the 295's aren't a problem with a 1" offset spring or the 4 link. Based on the measurements I've pulled off my Challenger and how tight I'm running the tire clearance on the rear of my Duster I think 325's are possible with the 1" offset.

The front has me a little confused. First, where are you measuring 19"? When I measure straight in from the center of the wheel opening, the tape measure lands into the shock tower, which is recessed. That gives me almost 19" to the fender lip, but that's not to the inner fender. If I move the tape forward or back so that it lands on the shock tower outer flange (where it's welded to the inner fender) I only get about 17-1/2". The measurement itself isn't super important, but we have to make sure we're using the same reference points to pull measurements from to compare numbers.

Next is the brake kit. Is this the stage 4 kit that Dr. Diff currently offers that has the brembo calipers and 13x1.25" rotor? If it is I know it only offsets the front track by 3/16" per side compared to the stock disks, which is the same as the Cobra style 13" kit I run on my Duster. That would put the 18x10's with 295's a full 1" closer to the frame rails than my 17x9's and 275's. While I do have some room to work with on the inside, I seriously doubt it's a full inch. I do know he's offered some variations of his kits though, so maybe it's an older kit with a different set up. If that's the case we need to know the exact increase in track width per side, because otherwise we really can't compare numbers.

I have heard that the Barracuda's have more room up front, but I don't have the measurements to prove it. On my Challenger with 275's I know for sure I can't go any further out toward the fender, although I do have some extra room on the inside. On my car at least I think 18x10's up front would be doable, and if I ran some additional backspace I think 285's would work. 295's I'm not so sure about, at least on my car. I'm limited to a 275 and a 9" rim because of the 17" diameter, the outer tie rod has very little clearance on my set up. With an 18" diameter rim the outer tie rod fits inside the rim, so, backspace can be increased until you run out of clearance on the frame at full steering lock.