67 dart rear end modification

[Greenmachine225]

Hey everyone, I had a couple of questions regarding some modifications I plan to make on my 67 dart drag car build. I plan to install a leaf relocation and mini tub in the rear to fit a larger tire but I’ve seen mixed information on how much to shorten the axle and the best wheel and tire combo to stuff under the rear. I’ve read a lot of discussions on the topic but I wanted to ask you guys myself. I’m building this car for the 1/4 mile and I figured I might as well go all the way so what set up is everybody running on their car and what would you guys recommend?

If anyone’s interested in what I’m building here’s some info on the car so far. 1967 dart gt, 440 big block- forged crank, eagle H beam rods, sealed power forged dome pistons about 11:1 compression with the heads im running. 906 heads ported, bigger valves and shaved .040. Bullet cams custom grind 267/275 573/590 on a 108 lobe separation. Mopar intake, Wilson’s 2 inch spacer and a custom 850 DP carb from Dominic Thumper. Trans is a 727 freshly rebuilt with some upgrades and a shift kit. And an 8 3/4 rear 4.10 gear in a 489 housing. I’ll post a couple pictures with this thread of the project so far. Haven’t fired it up yet but it’s almost ready to fire.

 

[Professor Fate]

Going "all the way" means different things to different people.
That said, unless you're back halfing the car, how much you narrow your rear is going to be limited by the frame rails. I will say this- don't cut your A body rear, it's worth a fair amount of coin as it sits. Get a comparatively cheaper B, C, or truck 8.75 since you're going to cut it anyway. Heck, if you're "going all the way", you should be looking at a Dana 60 anyways.

 

[Greenmachine225]

Going "all the way" means different things to different people.
That said, unless you're back halfing the car, how much you narrow your rear is going to be limited by the frame rails. I will say this- don't cut your A body rear, it's worth a fair amount of coin as it sits. Get a comparatively cheaper B, C, or truck 8.75 since you're going to cut it anyway. Heck, if you're "going all the way", you should be looking at a Dana 60 anyways.

i think you might be able to figure out what I meant by all the way from what I said( leaf spring relocation, mini tub and narrowed rear). And I’d rather just work with what I have instead of spending more money on a different rear end when I already have a good one. I guess I should just reword my question. What wheel and tire set up are people running with the spring relocation and mini tub, and did you have to shorten your diff at all?

 

[Garrett Ellison]

Power wise, you’re going to be right on the verge of what an 8-3/4 can tolerate. You should really run a back brace on the housing at this level. It’s been a while since I’ve seen what your looking at with the tire size after the three inch relocation, but @Oldmanmopar would probably be able to tell you. A stock width axle might be possible with enough positive wheel offset (a LOT of backspace). Great Looking Build!

 

[Garrett Ellison]

I meant to ask, are you going to run a custom converter with that?

 

[Greenmachine225]

I meant to ask, are you going to run a custom converter with that?

Yeah I forgot to throw that in there, it’s got a custom 9.5 inch converter from FTI. 4000 stall. And without shortening the diff I can fit a 15x10 and a 325 wide tire but I’d need 7.5 inches of backspacing. Might look a little weird with that much backspace so I figured I might as well shorten the diff. And yeah I definitely won’t be going past 550 wheel hp so I think the 8 3/4 should be fine for now. Years from now when I have a bunch more money I’ll go ahead and get a badass dana 60 for it. Also not a lot of wheel options for a 15x10 with over 7 inches of backspacing.

 

[Garrett Ellison]

From the sound of it, even though you’re probably going to have to shorten your housing to fit for available rims, there will still be some market for it in the future as there are many people with stroked small block or third Gen Hemi cars that find out they need to go the same route. It’s a long shot, but you may also be able to find someone who is going back the other way willing to trade your stock axle housing and shafts to a shortened one with axle shafts.

 

[MOPARMAGA]

So far ( under construction) I have a 41 inch flange to flange Dana 60 with us cartool relocation kit, using caltrac split monoleaf & assassin bars.
My Dana is a bit too narrow so I made some spacer plates to move the springs inboard an additional .750
I will be running 15×12 weld draglites with a 2.5 inch back space & Hoosier 29.5 11.5 w 15 which are 30.6 tall and iirc 13 inch tread

 

[Greenmachine225]

So far ( under construction) I have a 41 inch flange to flange Dana 60 with us cartool relocation kit, using caltrac split monoleaf & assassin bars.
My Dana is a bit too narrow so I made some spacer plates to move the springs inboard an additional .750
I will be running 15×12 weld draglites with a 2.5 inch back space & Hoosier 29.5 11.5 w 15 which are 30.6 tall and iirc 13 inch tread

Sweet thanks man! How do you like the caltrac and mono leaf set up? You said under construction so I’m going to assume you haven’t been able to test them out yet, so I guess quality wise do they seem worth the money?

 

[BrianT]

And without shortening the diff I can fit a 15x10 and a 325 wide tire but I’d need 7.5 inches of backspacing. Might look a little weird with that much backspace so I figured I might as well shorten the diff...Also not a lot of wheel options for a 15x10 with over 7 inches of backspacing.

When we mini tubbed my 67 this is exactly what we found. I had Strange build my S60 four inches narrower on each side (8 total) so that I could fit a 15X10 with 3 1/2" bs.

 

[MOPARMAGA]

Sweet thanks man! How do you like the caltrac and mono leaf set up? You said under construction so I’m going to assume you haven’t been able to test them out yet, so I guess quality wise do they seem worth the money?

Sorry, I haven't been able to test it out. I have a different traction bar it's from smith race craft and they offer a lot more tuning. Quality wise all of what I mentioned is great stuff, caltrac sliders are really nice too.
I can't wait to get it all together. I've started from scratch on my 70 dart just a decent slant 6 car getting drag race only treatment.

 

[KosmicKuda]

If it was me...I'd do the tub work and spring relocation first.

Then buy the 10" wheels and tires looking for the best deal on wheels without custom offset which adds additional money. Places like Summit often have "weird" offset wheels listed for half price because they're taking up space.

Roll them under the car and take measurements for rear end width and either shorten a housing, or buy new. Sounds like you are expecting to do that anyway.

 

[MOPARMAGA]

Hey everyone, I had a couple of questions regarding some modifications I plan to make on my 67 dart drag car build. I plan to install a leaf relocation and mini tub in the rear to fit a larger tire but I’ve seen mixed information on how much to shorten the axle and the best wheel and tire combo to stuff under the rear. I’ve read a lot of discussions on the topic but I wanted to ask you guys myself. I’m building this car for the 1/4 mile and I figured I might as well go all the way so what set up is everybody running on their car and what would you guys recommend?

If anyone’s interested in what I’m building here’s some info on the car so far. 1967 dart gt, 440 big block- forged crank, eagle H beam rods, sealed power forged dome pistons about 11:1 compression with the heads im running. 906 heads ported, bigger valves and shaved .040. Bullet cams custom grind 267/275 573/590 on a 108 lobe separation. Mopar intake, Wilson’s 2 inch spacer and a custom 850 DP carb from Dominic Thumper. Trans is a 727 freshly rebuilt with some upgrades and a shift kit. And an 8 3/4 rear 4.10 gear in a 489 housing. I’ll post a couple pictures with this thread of the project so far. Haven’t fired it up yet but it’s almost ready to fire.

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What time are you wanting to run with it ?
Nice car by the way!!

 

[MidnightSwinger]

I’ve got this one shortened to 45.75” and set up for spring relocation. I did a very rough mock up with an axle and drum installed and it looks like 15x10 with 4-4.5” depending on tire size/sidewall bulge.

 

[Greenmachine225]

What time are you wanting to run with it ?
Nice car by the way!!

I’m hoping for mid 11s but I’d be happy wait anything quicker than a 12. I’m setting my expectations a little lower so if I run quicker than 11.50 I’ll be super happy!