A body K member

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ethan santin

Buck eye jim you gotta go
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Hello there FABO,

Ive been looking at and potentially thinking about purchasing a 1967 barracuda V8 k member with motor mounts. I am planning on taking out the slant six drive line in my 1972 Duster and throwing in a small block and whole new drive line. Wanted to come on here and ask if a 1967 barracuda V8 k member will fit in a 1972 duster. I would also appreciate any advice or tips about switching out a slant six k member and swamping in a V8 k member. I understand that there might/will be complications with suspension and steering linkages but any additional information you guys could provide would be greatly appreciated.

Thank You
Ethan
 
If you have a choice, look for a 1973-76 K member. They have a better motor mount design and the better steering linkage.
A unit from 1968-72 is a good unit too.
SKIP the 1967 model. It will work but the idler arm mount is inferior to the 1968 and later models.
A 1973-76 model isn't hard to find.
Good luck.
 
if you're going to swap the K for a V8 conversion then look at 73~76 set up as K-dog said. for your purposes the 67 setup is going backward, if anything keep your current K and just get some swap mounts.
 
If you can fab, and can make a jig bracket, you could torch the idler arm mounts out of your 72 K and weld it into the 67. There was a thread recently on doing so, with pictures and ideas from previous threads on the subject.

You can also get aftermarket /6 to v8 conversion mounts but of course, money

And, you could also pull (carefully) the mounting towers off one K and weld it into the other, but this would require more jig/ brackets/ locating devices
 
Just buy the swap mounts for your '72 K. If you must buy a K, then '73-76 is the way to go as already mentioned. The '73-'76 K has the better spool mounts for the engine, and the sway bar runs through the K frame which improves ground clearance.

But yeah, also no issue with just running /6 to V8 conversion mounts for your current K frame. The '67 is the worst choice of all your options.
 
I would not be afraid of the 67 V8 K Frame. The only difference is the idler arm. Never had a 67 down idler mount fail. The rest of your linkage will work. I have actually replaced a 73 up K Frame with the 67 K Frame since the 73 up seem to made poorly and was busted up.
 
Don't use the 67 K-Member. You were warned here, They did away with that style idler arm for a reason. Without a through bolt they were a safety issue . Look for a through bolt idler style. 68-72 . The 73-76 spool mount style were great until they made interlocking biscuit style replacement mounts. Now they are just a used when you can't get the correct one you need.

There are also lower control arm supports on all cars that came with the stiffer torsion bars from 1970 and newer. These are identified by a washer welded to the front. They did this due to problems with the control arm pins busting the k-member with the stiffer bars and stabilizer bar. First picture is a standard style and second picture is Heavy duty. I also included some side by side pics of the biscuit and spool mount style for your reference. As you can see the spool type makes it tight for some headers clearance. The choice of headers can make a difference.

DSCN1651.jpg


DSCN1652.jpg


susp1.jpg


susp2.jpg


susp3.jpg


susp4.jpg


susp5.jpg
 
Nothing wrong, especially safety wise with a 67 Idler mount. I call BS here. I have a 67 Barracuda with 400,000 miles on it no problem with the Idler mount. Worry about something else. The only K Frame I have seen messed up is a 73 up due to sloppy or non-existant welds. It was replaced with a 67 K frame and is probably still fine.
 
The resistance to going with the 1967 unit is entirely based on the idler arm mount.
They are not as rigid but for easy cruising, it would be fine.
The idler mount would probably only be a problem in a car with wide tires set up for cornering or on rough roads. The resistance to deflection is greater with the 1968 and later models.
I aim for what works best in a handling application.
 
67 idlers are expensive and hard to get. You can likely buy a different K for the price of one. As I said earlier, since he has a later UNWANTED K, he could weld the later mount into the 67 and convert it. I see NO reason to stay with a 67 idler
 
67 idlers are expensive and hard to get. You can likely buy a different K for the price of one. As I said earlier, since he has a later UNWANTED K, he could weld the later mount into the 67 and convert it. I see NO reason to stay with a 67 idler

I know, and I would not bother changing anything on a 67 K Frame. I'll take the factories precision over some one elses fabrication. The 67 idler mount is tapered like a tie rod end so it locks in place. I do cheat and use an even more expensive tapered needle bearing idler rather than stock. Also on my 68. My brothers car was never babied and handled extremely well. Think 5 plus years of rural South Dakota, gravel roads and 400,000+ miles in all. You guys simply do not have the experience with the earlier cars. That idler is expensive, but there is no problem running one. I also put over a quarter million miles on my 64 and 66 Barracuda with the same idler mount. Never problem one and both cars handled very well with wide performance high speed radials.
 
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Was the oddball idler arm a 67 A body only item, or did B and C bodies also get them?

B bodies had them too and changed over in '68 just like the A-bodies. C-bodies were using the later style in '65, not sure about earlier.

I'll take the factories precision over some one elses fabrication.
:rofl:

You mean, the factory that couldn't get the suspension mounts located with better than a 1/4" tolerance? The factory welds that look like a blind guy did them? C'mon man. These cars were spot welded together on an assembly line that emphasized speed over quality. Anyone with a plumb bob, some basic geometry skills and a Harbor Freight welder can surpass the "factory precision"


Never problem one and both cars handled very well with wide performance high speed radials.

Uh huh. How wide were those performance high speed radials? And what was the tire compound rated at?

Ma Mopar ditched that design 55 years ago because it was sub-par. Like 9" drum spindles, it was a poor design that was identified by the factory and replaced with improved, redesigned parts at great cost to the factory. That's not the kind of thing that the factory does just for fun, there was absolutely a reason for it. Maybe that reason wasn't outright failure, but they still decided it was worth the cost in the long run to change the design.
 
as mentioned already why spend money and time swapping out the k member when you can buy conversion mounts to bolt a v8 to your /6 k member? even if the mounts are 2-3 times the cost of the 67 k member the time saved by simply bolting the motor to what you have is easily worth the extra cost. it's a no brainer really.
neil.
 
you could upgrade the 68~72 or 73~76 arm to a roller bearing and be cheaper than just the 67 arm. sheesh!

hell, you could probably grab a new idler and K for the price of that arm!

i've personally torn the mount on four different 64~66 cars (same design) with "only" 205's fitted-- granted, performance/track tires). and had a client start to pull one on his 67 dart with a 383.

understandably, on my early A's that was absolutely above and beyond any kind of normal conditions of use, but on that 67 383 car the dude is a old man cruiser rolling on 14's still.

i converted the early K to double shear and ran the later arm, on the 67 i wound up swapping the K to 73~76 when he opted to go BBP brakes.
 
Pencil it out. It's mainly a matter of cost. Conversion mounts for your existing K-member and you save the labor changing it, buy and convert to the '67 idler and swap the K-member, or buy a '68-72 V-8 K-member or the 73-6 V-8 K-member and stock motor mounts and swap those in. For street use, any of those are decent options. For performance use, The last two or aftermarket K-member would be better. The stock K-members need rewelding and gussetting to fix sloppy factory welds and to reduce flex. The level of performance can escalate the cost significantly.
 
A. Conversion Mounts

B. 68-72 K-frame (my personal preference)
New idler
Reuse all other existing components

C. 73+ K-frame
New idler
New center link
New pitman arm
If you have a sway bar, new control arms, new bar.


At least that is the way I understand it.


Alan
 
B bodies had them too and changed over in '68 just like the A-bodies. C-bodies were using the later style in '65, not sure about earlier.


:rofl:

You mean, the factory that couldn't get the suspension mounts located with better than a 1/4" tolerance? The factory welds that look like a blind guy did them? C'mon man. These cars were spot welded together on an assembly line that emphasized speed over quality. Anyone with a plumb bob, some basic geometry skills and a Harbor Freight welder can surpass the "factory precision"




Uh huh. How wide were those performance high speed radials? And what was the tire compound rated at?

Ma Mopar ditched that design 55 years ago because it was sub-par. Like 9" drum spindles, it was a poor design that was identified by the factory and replaced with improved, redesigned parts at great cost to the factory. That's not the kind of thing that the factory does just for fun, there was absolutely a reason for it. Maybe that reason wasn't outright failure, but they still decided it was worth the cost in the long run to change the design.

Say or believe what you want, I'd never cut off a 67 idler bracket to install the 68 sheet metal bracket. Neither would I go the other way. Not even close to the 9 in brake comparison.
235 wide long before compounds were rated. I was also one of the first to use Poly bushings back when you had to reuse the metal parts from your old bushings.
Not sure why they changed design, may have been cost also. You can think the newer design is stronger if you want. I would never bother changing a 67 idler mount. I look at them as the same. I doubt he OP would see any difference. You guys like to do a lot of work for little or no gain.
 
A. Conversion Mounts

B. 68-72 K-frame (my personal preference)
New idler
Reuse all other existing components

C. 73+ K-frame
New idler
New center link
New pitman arm
If you have a sway bar, new control arms, new bar.


At least that is the way I understand it.


Alan

The OP already has the ‘72 K frame in his car, it’s just for a /6. So he could just do conversion mounts and change nothing else. That will be cheaper than the ‘67 v8 K he’s looking at just on the cost of the ‘67 idler.

For the ‘73-76, you don’t need to change the pitman, idler, or center link. He could keep all of the ‘68-72 parts if he keeps his current steering box. You just can’t mix and match, if you use a ‘73+ pitman you also need the ‘73+ center link and idler. Those three parts have to match the year range, either ‘68-72 or ‘73-76. Change one and you need the other two. But you can use a ‘68-72 pitman, idler and center link with the 73-76 K frame as long as you don’t use a large sector power steering box.

The sway bar brackets on the LCA’s are different 73-76, so, if it’s a ‘68-72 factory sway bar car using the 73-76 sway bar would mean changing the brackets on the LCA’s too.

Say or believe what you want, I'd never cut off a 67 idler bracket to install the 68 sheet metal bracket. Neither would I go the other way. Not even close to the 9 in brake comparison.
235 wide long before compounds were rated. I was also one of the first to use Poly bushings back when you had to reuse the metal parts from your old bushings.
Not sure why they changed design, may have been cost also. You can think the newer design is stronger if you want. I would never bother changing a 67 idler mount. I look at them as the same. I doubt he OP would see any difference. You guys like to do a lot of work for little or no gain.

Hey I wouldn’t cut the bracket off a ‘67 K frame either! Of course, it’s because I wouldn’t ever buy a ‘67 K to begin with, the factory literally made them obsolete in 1968. The ‘73-76 sway bar provision is worth the upgrade to the ‘73-76 K by itself. Better ground clearance, better tire clearance for wide front tires (245 or better).

235’s aren’t wide, and if they pre-dated compound ratings then they were much harder than what you can get now. 275’s with 200 tread wear compounds are not even in the same ballpark as those old 235’s.

As for the 9” spindles, well, there’s plenty of people here that defend them. So they must not have seized up the undersized wheel bearings or sheared the undersized lower ball joint bolts. But hey, that doesn’t mean that other people didn’t. Much like your take on the ‘67 only idler. Awesome, you didn’t have a problem with it. Other people definitely have had issues with it.

And if nothing else, the ‘67 idlers are stupid expensive. The OP doesn’t have to deal with the ‘67 K or idler at all, and there’s no reason to even from just a financial stand point, let alone a performance one.
 
Don't forget that whatever V8 you install, you will need the matching engine brackets; AND passenger side mounts are different between the 273/318, and the bigger SBMs.

340s work great in these cars.
A hi-compression 4-bbl318 is also a good choice.
A 273 can be a nice cruiser .
But a hi-compression 360 streeter is/can be, borderline overkill.
 
Hey I wouldn’t cut the bracket off a ‘67 K frame either! Of course, it’s because I wouldn’t ever buy a ‘67 K to begin with, the factory literally made them obsolete in 1968. The ‘73-76 sway bar provision is worth the upgrade to the ‘73-76 K by itself. Better ground clearance, better tire clearance for wide front tires (245 or better).

235’s aren’t wide, and if they pre-dated compound ratings then they were much harder than what you can get now. 275’s with 200 tread wear compounds are not even in the same ballpark as those old 235’s.

As for the 9” spindles, well, there’s plenty of people here that defend them. So they must not have seized up the undersized wheel bearings or sheared the undersized lower ball joint bolts. But hey, that doesn’t mean that other people didn’t. Much like your take on the ‘67 only idler. Awesome, you didn’t have a problem with it. Other people definitely have had issues with it.

And if nothing else, the ‘67 idlers are stupid expensive. The OP doesn’t have to deal with the ‘67 K or idler at all, and there’s no reason to even from just a financial stand point, let alone a performance one.

Well we can agree to disagree. Your race car stuff does not translate to 50 years and 600,000+ miles of experience. I even checked my 67 big block K frame, idler mount is still good.
 
Well we can agree to disagree. Your race car stuff does not translate to 50 years and 600,000+ miles of experience. I even checked my 67 big block K frame, idler mount is still good.

Lol! “Agree to disagree” and then try and big league me. Ok pal.

The “race car stuff” on my Mopars has done well over 100,000+ miles of street driving. My Challenger and my Duster have both done daily driver duty, my Challenger for over 8 years straight as my only car and my Duster since then. I drive my Duster a minimum of 120 miles a week as long as there aren’t chain restrictions up for snow. Heck up until 2 years ago my Duster was the newest car I owned.

I’ve worked on classics for over 30 years, and have used them as my daily’s pretty much the entire time I’ve had a license, over 28 years now. Heck I daily drove a ‘56 Austin Healey for years.

If after all of your time and experience you can’t understand why a single shear idler mount is inferior when compared to a double shear mount, clearly there’s no point in trying to explain it. Chrysler engineers decided it was a poor design over 50 years ago. If you want to run obsolete stuff that’s fine, that’s part of driving classics. But pretending it’s just as good as later, improved designs just shows your lack of knowledge, in spite of all your experience.
 
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