/6 K-Frame vs. V8 K

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Golden Scamp

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I need to know before i make an expensive purchase if the /6 K is the same as the V8 K in every aspect except position of mounts. I am transplanting a 383 into a 68 Dart with the / and would need to know if there are differences. If I can just put in some Shumacher mounts and convert, awesome, but if a V8 K has any dimensional or structural differences, can someone give me some feedback. Need to get some answers before 8 AM and can't find much about online. Thanks Guys!
 
The later model spool type k-members are /6 and small block specific. The mounts are off set for the /6. But like you said, mounts are made for swaps.
 
Here are the details for the 67 to 72 A-body K frames.


There are several ways to determine whether a 67-72 A-Body K-member is a S6 or V8.

With the motor in car, measure from the frame rail to the side of perch.

The V8 should measure approximately 4" across.
The S6 should measure approximately 2" across.



If the engine is not installed, you can measure across the top from perch to perch.

The V8 should measure approximately 20" across.
The S6 should measure approximately 22 1/4" across.
 

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The one I'm looking at is a SB 68 biscuit mount K. ID is not a problem, but does it make sense to get a Small block V8 K and have to put in mounts to convert to a BB instead of using original /6 k and adding BB mounts to it? I'm asking if the /6 is in any way less up to the job than the SB 8? Should I look for the V8 or am i wasting my time because the mounts will be similarly priced and there is little diff between the 6 and 8 strengthwise/structurally? Dont want to be ready to drop the motor in and find /6 K has to be hacked all over to make 383 fit. Thanks for all of the pics BTW!
 
For instance, will all front suspension route through the /6 and v8 k's the same? Will suspension clear? I'd like to think the v8 would be a better fit, but I don't know.
 
None of the suspension routes through the K-frame on the 72 back. All suspension is the same on the 68 to 72 K-frames. 1967 is the same except the idler arm and that part is a one year part. The sway bar routes through the K-frame 0n the 73 up. In other words the 73 up sway bar set up will only work if you cut the earlier K-frame.

It is said the 340 K-frame is better constructed than the regular V8 frame and has rear supports. The 340 K-frame can be identified by the washer that is welded on it.

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EDIT, LOL I was typing as Okla was posting


The only suspension differences I know of are...........

The 67 only K has a single year idler mount, but you could fab that one to take later Idlers

The 73/ later K's run the factory sway far through the middle of the K, so a couple inches more clearance and a cleaner look.
 
So then the only difference in the K frame itself, 68-72, is the mounts? V8 is not beefier? Frames are of identical size/strength? Appreciate all of the insight from you guys. Just don't want to make the mistake of overloading a part that wasn't designed for the amount of power from a Big Block.
 
So then the only difference in the K frame itself, 68-72, is the mounts? V8 is not beefier? Frames are of identical size/strength? Appreciate all of the insight from you guys. Just don't want to make the mistake of overloading a part that wasn't designed for the amount of power from a Big Block.

They are the same dimensions where they bolt to the frame rails.
340 K-frame is said to be beefier as shown above.
The /6, 273 and 318 are the structure with different mounts.
The only problem area is always the lower control arm mounts are welded. I would beef that area up no matter what.
 
Where is that washer welded on at on the 340 K?

Somewhere on the front middle. It does vary in that area since it appears that it was just tacked on for identification purposes. I have one out back that is out of a 340 car with a sway bar and Kelsey Hayes disc brakes and it has the washer. All of them may not have the washer from what has been said.

Sample pictures.

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My understanding is the washer is 70-later thing or thereabouts. If you want to beef up the LCA pin tubes go ahead, but you will likely gain nothing changing to a V8 k-member because it is likely that none of the critical areas are different because it is likely to be a 318 k-member.

BUT, if you can get a 73-76 V8 k-member with spool mounts you can build a big block k-member out of it without needing Schumacher mounts...
 
I was just looking over the pictures above and the '67-69 A-Body Original B/RB K-Member clearly has those half moon/C washers on the lower control arm pivot mount but the V8 biscuit mount K frame doesn't have the half moon/C washers. Members have posted quite a few threads with them broken and wallowed out so I would add them.
 
Add says out of a 71 340 car. Don't see any washer, though. Sounds like what I have now is going to be good enough and just needs conversion mounts. Thanks again. Great support.
 
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