235 70 15 rear early abody

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JohnnyDart why dont you bring your garage queen to Irwindale speedway next thursday so i can show you what a firecracker is? Bring a 100 bucks too, and i never said anything about knowing more than Dutra i get most of my build advice from him, the man is a legend.

No problem....Make sure you have your 235/70-15s on. :)
 
I use to have a 70 duster with a 225 /6 with dragrite 60s x15” and that little coffee can car would blaze the rear tires,,,,so I believe in the FIRECRACKER theory.
 
255/60-15 under my 66 valiant , stock location , ss springs
 
I guess the question should be:
1. "Will 235/70 15's fit in my early A body"

OR

2. "Should I try 235/70 15's on my early A body?"

The answer to #1 is in most A bodys yes it should fit. But the answer to #2 is depends on a few factors.
What is the implied use going to be? 100% freeway or 100% drags or a mix.
What is the rear end gear ratio? 2.45:1 then NO it will be a dog off line. But 4.56:1 then yes.
A quick check. Say a 65 Dart came with A-78 13's (155/78 13) and you want to go to 235/70 15. At 65 MPH your RPM's in the following gears:
2.76:1 = 2640 vs 2130
2.94:1 = 2851 vs 2297
3.23:1 = 3110 vs 2500
3.55:1 = 3440 vs 2774
4.56:1 = 4422 vs 3563

So say you have 3.55:1 gears and you take your A-78 13 off and put this 235/70 15 on it would be ALMOST like replacing your rear gears to 2.94:1 with the A-78 13's.... Good for commuting, not good for drags or Stop-Light to Stop-Light....
But if it were me, I have an extra set of wheels mounted with some 275/50 15 Hoosier R7 drag radials for my track only days.... I have these for my LRT on extra LRT 8 inch rims.

YMMV ;)
 
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I ran 235-60-15’s with a 7” wheel before I went to a mini tub. With people in the back it would rub occasionally.

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I ran 235-60-15’s with a 7” wheel before I went to a mini tub. With people in the back it would rub occasionally.

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What rear end were you running in the car when those pics were taken? I love the way it sits! Do you know what the back spacing on the wheels is? I have a 65 Barracuda I'm fixing up, and going to big bolt pattern all around. I have my choice of using and A body 8 1/4, or an A body 8 3/4 with Dr. Diff axles and drum brakes that fit the axles. I have some 15 x 7 aluminum mags, and I'd love to put 235-60/15's on the back if possible.
 
What rear end were you running in the car when those pics were taken? I love the way it sits! Do you know what the back spacing on the wheels is? I have a 65 Barracuda I'm fixing up, and going to big bolt pattern all around. I have my choice of using and A body 8 1/4, or an A body 8 3/4 with Dr. Diff axles and drum brakes that fit the axles. I have some 15 x 7 aluminum mags, and I'd love to put 235-60/15's on the back if possible.
On post #18 I posted a picture of my 1965 Barracuda with a Dodge Aspin 8 1/4 and 275/60 15's on 7 inch Dodge Cop Car wheels.
They do rub the springs when I corner a bit too fast and on the outer fender only when I have two people in the back seat. But for years I ran 245/60 15's on that same rim.
 
Thanks! Odd thing is, my Barracuda has an FMJ 8 1/4 in it right now...lol. It looks 47 miles wide, and has crappy old tires on it. It’s cobbled to hell and back by whoever put it in, so I will have to fix all that if I were to keep it in there. I’m thinking I may use a stock width A body 8 3/4, and use Dr Diff’s half inch narrower spring perch kit to gain a tiny bit of room. If this thing ever has enough power to need 275’s, I’ll mini tub it and move the springs to the frame rails.
 
So i ended up picking a rim and tire set up for my 64 going with 14x7 225 70 14 in the rear i like the way Mikes 66 Looks only thing is i will use 14inch rim than a 15inch. and i will reuse my front tires 215 70 14 just put them on a 6 inch rim instead o the stock 4inch or whatever size it is. Thanks everybody
 
Someone tell me what max tire is in a 65 Barracuda with a stock A 8 3/4 rear. 205/70R14's currently on rallies. Want to go 15's as i have 15x7 SBP reverse Centerlines from a Chevy 2 so they are more back spaces than front. Maybe 5 back and 3 front. Redrilled.
 
Someone tell me what max tire is in a 65 Barracuda with a stock A 8 3/4 rear. 205/70R14's currently on rallies. Want to go 15's as i have 15x7 SBP reverse Centerlines from a Chevy 2 so they are more back spaces than front. Maybe 5 back and 3 front. Redrilled.
i seen 255 60 15 on the rear of an early abody back spacing 4.5 i think he said
 
Someone tell me what max tire is in a 65 Barracuda with a stock A 8 3/4 rear. 205/70R14's currently on rallies. Want to go 15's as i have 15x7 SBP reverse Centerlines from a Chevy 2 so they are more back spaces than front. Maybe 5 back and 3 front. Redrilled.
OK, STOCK 7 1/4 was a A78 13 that is close to a 155/78 13.

The upgrade was D70 14 and that was about a 165/70 14. So that should have been used for any 65 Formula S. But the 1964-1966 Barracuda's got a bigger rear wheelwell than most of the other A bodys so you can fit a bigger tire under one than a Dart/Valiant.

Using a 1974 Dart Swinger 7 1/4 LBP axle and SS springs, I had 245/60 15's under my 1965 Formula S Barracuda on 5.5 inch Mopar rallys for a few years and NEVER rubbed.

Currently have 275/60 15's on Cop Car ralleys under it but they do rub.
 
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My brothers, original paint, 35k miles
255 60 15 on 15x7 with only 4in BS
Car has air shocks
 
Firecracker ?
What kind of hp are we talking here ?
I have a 1970 HotRod magazine article, with a Guru Doug Dutra /6 build. With every trick part, and his knowledge thrown at the motor, trans, car weight, on and on. He came up with a whopping 167.6hp at 4500rpm 14.926 at 78.73. And guess what rear tire he used ? He used a 13"x7" rim with a 24.5" tall tire !!!!!! Why did he do that you ask ? Because he didn't want to dog the little 6 with a big *** tire. Most people understand rotating mass, and unspring weight. Google is your friend.
I really could care less what tires you run, but I got $100 your car will be quicker with a smaller tire than the tire you are suggesting. Than again, I'm sure you know more than Dutra.
PS: I have a car with the same firecracker crap as you, i know what I speak..

Doug Dutra is certainly a slant legend genius, no doubt. But that doesn't mean someone else cannot build faster slant six equipped car. There's always somebody with something faster.
 
Doug Dutra is certainly a slant legend genius, no doubt. But that doesn't mean someone else cannot build faster slant six equipped car. There's always somebody with something faster.

You are missing my point.
My point is that after all the shite Doug did to this car, all it could muster was a 15sec quarter.
 
You are missing my point.
My point is that after all the shite Doug did to this car, all it could muster was a 15sec quarter.

No, I got it. A lot of his projects have been what some would consider "failures". I don't necessarily see it that way. I think he tries things differently than others hoping to find "that result" that no one else has. He's pretty innovative. How many times did famous inventors fail before they were successful? A LOT.
 
Its about 1/4" difference fronts would be 5.9" and rear sidewall is 5.6"

I can see it now....
Driving down the road at 45 MPH and a dude runs up and says "Man, your rear tire is 3 tenths shorter than your fronts". ;)

For years I ran a 255/70 15 on front and 275/60 15 on the rear of my 78 LRT and no one said anything. Its what I had and from 20 feet away it looked ok.
 
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