70 Dart Swinger with 275/60/15 E/T drag

-

m79ded

FABO Gold Member
FABO Gold Member
Joined
Nov 21, 2017
Messages
109
Reaction score
50
Location
NY
Hi
I would like to ask if I can fit a Mickey Thompson ET-Drag-R 275/60/15 in a 70 Swinger without touching the 1/4's. It's a nice 340 car and would really not want to cut the car. Can it be done with proper offset?
Would like to hear from owners that had this dilema and what was the results.
Thanks
 
I think that will be too tall and contact the forward edge of the wheelwell, I had 245/60 15 BFG drag radials on my 70 IIRC, and they were pretty close. Unless you move the springs inboard I doubt there will be enough room, even then it will probably still be tight.
 
I have put a 265/60/15 on one with a 15×8.5 with 4 7/8 backspace.....some cars have more room...guy down the road put a 275 on his...I could not ..it rubbed lip on sharp curves and quick turns...265 was gold!!!
 
I have 255-15's on 15x7 with 4.25 backspace. It's damn close to the quarters and not much room to the springs.

001.jpg


20160518_170052.jpg


20160518_170457.jpg


20160518_170550.jpg
 
They will physically fit in there, but
you might have to move stuff around, and get custom wheels; not a huge deal
IIRC 275/60-15s are just about exactly 28" tall. During launch, they will move slightly forward, so you'll need a minimum of .375 inch clearance.
If your car is lowered, don't forget the hump in the top of the tub likes to get into the tire on bumps, like the ridge above the wheel arch. Stick your head in there and eyeball this stuff before you spend your money.
Some guys shim the front perches but I don't think you can get more than .25 there, unless you swap out the factory length studs.. So the next go-to is to move the entire rear end back on the springs, and make sure it stays there. Both of these will pull the driveshaft out of the trans a like amount, but in my case it was no bother.
Depending on your spring arch, you may have to re-engineer the rear shackle angles. Plus clearance the tank for shock-body clearance.
All doable solutions, for the 28s
If you already have your wheels purchased and you are particularly attached to them, them, you may have to narrow the rear end and move the springs inboard; also doable.
275s want to be on 9" or wider rims. But that may put the sidewalls into the springs. For straightline work they will fit on 8s. But to run on the street like that, you may have to drop the tire pressure down to 26 or maybe 24, for long treadlife. Then, in the turns, they may get back into the springs as the body shifts over. So slow down until you get everything clearanced just right.
It's a bit of a battle but totally doable, and to my recollection, that particular combo needs all the tire it can get, and slapper bars besides,lol.

Happy HotRodding.
 
Last edited:
On a ‘70 Dart Swinger you won’t get 275’s in there without a 1/2 spring offset, it can’t be done with the springs in the stock locations.

Even with the 1/2” offset it will be close, some cars might still need to trim the quarter lip depending on ride height, suspension, and body tolerances. Some won’t, but if your intention is absolutely not to do any trimming I would suggest doing a test fit even with a 1/2 spring offset before you pulled the trigger on new wheels.

I have put a 265/60/15 on one with a 15×8.5 with 4 7/8 backspace.....some cars have more room...guy down the road put a 275 on his...I could not ..it rubbed lip on sharp curves and quick turns...265 was gold!!!

They will physically fit in there, but
you might have to move stuff around, and get custom wheels; not a huge deal
IIRC 275/60-15s are just about exactly 28" tall. During launch, they will move slightly forward, so you'll need a minimum of .375 inch clearance.
If your car is lowered, don't forget the hump in the top of the tub likes to get into the tire on bumps, like the ridge above the wheel arch. Stick your head in there and eyeball this stuff before you spend your money.
Some guys shim the front perches but I don't think you can get more than .25 there, unless you swap out the factory length studs.. So the next go-to is to move the entire rear end back on the springs, and make sure it stays there. Both of these will pull the driveshaft out of the trans a like amount, but in my case it was no bother.
Depending on your spring arch, you may have to re-engineer the rear shackle angles. Plus clearance the tank for shock-body clearance.
All doable solutions, for the 28s
If you already have your wheels purchased and you are particularly attached to them, them, you may have to narrow the rear end and move the springs inboard; also doable.
275s want to be on 9" or wider rims. But that may put the sidewalls into the springs. For straightline work they will fit on 8s. But to run on the street like that, you may have to drop the tire pressure down to 26 or maybe 24, for long treadlife. Then, in the turns, they may get back into the springs as the body shifts over. So slow down until you get everything clearanced just right.
It's a bit of a battle but totally doable, and to my recollection, that particular combo needs all the tire it can get, and slapper bars besides,lol.

Happy HotRodding.

Seems like both of you are talking about Dusters/Demons/Dart Sports.

A ‘70 Dart Swinger like the OP is talking about has a full 1” less room than the “sport” body style. Even with a 1/2” offset 275’s are super close on the hardtop Darts.
 
Well I was also looking at a Demon as well, It's for a street/ monthly track duty car, I guess it probably be much easier with a Demon. I sold my Duster and I sure miss that that A Body. Let me know of a decent one for sale in the Northeast, Thanks
 
Seems like both of you are talking about Dusters/Demons/Dart Sports.
My 68 Barracuda accepts 325/50-15 DRs on 10s, with just the spring offset, and properly centered, even at my lowered ride height......but spirited cornering is somewhat limited. I narrowed the rear for no other reason than to use the 4.5 backspace of the period aluminum slot-mags I so loved. The 295s have tons of room in there.I imagine the other big-tub cars would be similar.
275/60s are about 10.8 section width on 8s, and I thought the Dart tubs are about an inch bigger, depending on where you measure from. Am I wrong?
 
My 68 Barracuda accepts 325/50-15 DRs on 10s, with just the spring offset, and properly centered, even at my lowered ride height......but spirited cornering is somewhat limited. I narrowed the rear for no other reason than to use the 4.5 backspace of the period aluminum slot-mags I so loved. The 295s have tons of room in there.I imagine the other big-tub cars would be similar.
275/60s are about 10.8 section width on 8s, and I thought the Dart tubs are about an inch bigger, depending on where you measure from. Am I wrong?

Barracuda’s have similar wheelhouses to the Duster/Demon/Dart Sport, if anything the Barracudas seem like they have even more room than the sport body’s. The inner wheelhouses are all the same but the outers are different. On a ‘70+ Dart/Scamp there’s only ~11” from spring to quarter lip. So a 10.8” or 11” section just won’t work.

On a Duster/Demon/Dart Sport there’s about 12” from spring to quarter lip with the stock spring locations, which makes 275’s fit just fine.
 
Last edited:
A little lift in the back lets the outboard sidewalls breath about another inch. The tread is still in the tub .......
My experience with Darts as to traction, is that they need all the tire they can get. That's why I don't have one anymore. If I did, I would make those 275s fit;whatever it took. And if I couldn't, I would leave the 318 in there.
I am not a straightline point and shoot guy. Which 255s are already not much good at for a performance SBM. I need me some sideways rubber, cuz around town, you never know what the corner will bring; and the brakes don't work when sliding sideways; and aluminum wheels can't take bouncing off curbs..
I'm not talking about drifting every corner in traffic.
I'm talking about pushing the envelope just a little to have some fun; just spirited driving. I'm not a fan of spinning out and facing backwards. Which is what skinny-tired Swingers are real good at.
I've got a few hundred thousand miles experience with those cars, and a Leopard don't change his spots; I've been driving "spiritedly" since 1969. I used to slide a 340 Dart around in traffic pretty good, cuz that is what they do. It can't change it's spots either. All you can do is put the tallest widest tires in there and learn to deal with that overhang back there.

I think my 325s have over a 13" section; 13.3 rings a bell. It fit's real nice in my factory Barracuda tub, with the outboard sidewall about flush with the body line. At my lowered ride-height, those are mostly point and shoot. I rarely install them.

The question was;
Can it be done with proper offset?
Would like to hear from owners that had this dilema and what was the results.

The answer is; with no other changes; no.
But if you move stuff around a bit, yes.
 
On a ‘70 Dart Swinger you won’t get 275’s in there without a 1/2 spring offset, it can’t be done with the springs in the stock locations.

Even with the 1/2” offset it will be close, some cars might still need to trim the quarter lip depending on ride height, suspension, and body tolerances. Some won’t, but if your intention is absolutely not to do any trimming I would suggest doing a test fit even with a 1/2 spring offset before you pulled the trigger on new wheels.





Seems like both of you are talking about Dusters/Demons/Dart Sports.

A ‘70 Dart Swinger like the OP is talking about has a full 1” less room than the “sport” body style. Even with a 1/2” offset 275’s are super close on the hardtop Darts.
Are the later darts 73-76 the same dimensional at the 70s? It seems to me the later ones are a little tighter I'm not sure if the wheel wells are smaller or the leafs are farther out but iv seen 70s and 71s and they appear to have more room than my 75
 
-
Back
Top