Tubular k vs factory k

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Paul Davidson

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I'm thinking of converting to a tubular k frame from a stock one not sure how strait my original is. And I'm having issues with header fitment and stearing box hitting headers that I didn't have before also I'm converting to a 360 from a 273 any help is appreciated
 
Hi Paul,

This topic has been discussed to death so here's how to access any info you may need.
In the top right corner of this page is a box marked search.

Type in" tubular vs stock K-member " and you will get pages and pages of discussion on this topic.

Hope this helps.

Cheers!!
 
And I'm having issues with header fitment and stearing box hitting headers that I didn't have before …

How are your door gaps? Do you have any frame stiffening, ie. torque boxes or frame connectors?
 
And I'm having issues with header fitment and stearing box hitting headers that I didn't have before also I'm converting to a 360 from a 273 any help is appreciated
If the headers fit before with a 273, and they don't fit now with a 360; then you changed something else or you have something installed incorrectly. There should be no issues now with header fitment that weren't present before. Did you re-use the 273 mounts, or buy adapter mounts? Which ones? New or different biscuits? Which ones?
More info and pics or at least a description of the trouble area(s) would go a long way in figuring this out.
 
I believe the QA1 K-member is the only one that uses the stock steering box.

It's designed to keep the motor, steering box, headers, oil pan and suspension all in the same location relative to each other.

So if you are having an issue between those items, there shouldn't be change with a QA1 k-member.

If you are having a clearance issue between the stock K-member and one of those items, then a QA1 k-member may change that.
 
What car, what headers, what steering box, and what changed other than the 273 to 360?
 
What car, what headers, what steering box, and what changed other than the 273 to 360?
Ok 67 barracuda had 273 with hooker headers and stock stearing box.
Installed frame connectors 360 and dougs headers also tried borgeson box header hit both boxes
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oh boy. here we go yet again.

best bet is to use the search feature. this topic comes up atleast once a month.
 
Ok 67 barracuda had 273 with hooker headers and stock stearing box.
Installed frame connectors 360 and dougs headers also tried borgeson box header hit both boxes View attachment 1715958509 View attachment 1715958512 View attachment 1715958512View attachment 1715958513View attachment 1715958514

The Doug’s should clear the manual steering box no problem. I have Doug’s on my 340 and no issues with a stock manual box or the Flaming River manual box which is slightly larger.

The Boregeson interference isn’t totally surprising, those headers were never designed for that box. It also looks like a couple of small dimples might solve the problem, and a couple of small dimples in the headers are par for the course with A-body headers because of the tight clearances and loose factory tolerances.

Are your engine mounts new? If they’re worn out you may need to shim up the engine on one side or the other. Shimming the engine mounts is a fairly common solution to getting the headers to fit a particular car. There are A LOT of threads on here about getting headers so fit different combinations.

Are Dougs designed to be used with power steering boxes? I thought they were a manual steering only deal.

The Doug’s should clear factory power steering boxes. But they were definitely not designed for the Borgeson, so even though the Borgeson is overall smaller there may be some tight spots. @BergmanAutoCraft would probably know
 
How was the car supported (jacked up) when the Sun-frame connectors were welded in? If it was tweaked a little when they’re welded in the body will stay that way.
 
The Doug’s should clear the manual steering box no problem. I have Doug’s on my 340 and no issues with a stock manual box or the Flaming River manual box which is slightly larger.

The Boregeson interference isn’t totally surprising, those headers were never designed for that box. It also looks like a couple of small dimples might solve the problem, and a couple of small dimples in the headers are par for the course with A-body headers because of the tight clearances and loose factory tolerances.

Are your engine mounts new? If they’re worn out you may need to shim up the engine on one side or the other. Shimming the engine mounts is a fairly common solution to getting the headers to fit a particular car. There are A LOT of threads on here about getting headers so fit different combinations.



The Doug’s should clear factory power steering boxes. But they were definitely not designed for the Borgeson, so even though the Borgeson is overall smaller there may be some tight spots. @BergmanAutoCraft would probably know
I had a stock ps box when I started still didn't fit tried shims no luck been working with this for a while the amount of dimple in that tube would be significant and the header would be very close to the stearing box
 
How was the car supported (jacked up) when the Sun-frame connectors were welded in? If it was tweaked a little when they’re welded in the body will stay that way.
The car was on my lift but leveled and made sure doors didn't bind and k frame bolted back in without any problem
 
The reason I was thinking of a tubular k is the lack of quality control on most mopar bodies and k frames maybe my k is on the extreme limits of all their specs.
 
Motor mount "looks" a little old. But seems like you need to move away more than just one replacement mount.

I believe they make a truck mount that is thicker. But looks like you're going to need a dimple. Dimple it and shim it... and move on

I don't think its cost effective to buy a new K-member purely to take a chance that it solves this ? 1/2" clearance issue. The money, time, effort just to bank on 1/2 quality control (dimensional stack up) is too risky.

Not that is bad, but looks like there is an repro motor mount bracket used. Just another variable.

upload_2022-7-20_10-10-57.png
 
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If the headers fit before with a 273, and they don't fit now with a 360; then you changed something else or you have something installed incorrectly. There should be no issues now with header fitment that weren't present before. Did you re-use the 273 mounts, or buy adapter mounts? Which ones? New or different biscuits? Which ones?
More info and pics or at least a description of the trouble area(s) would go a long way in figuring this out.
Okay, so you've changed a ton of stuff, so comparisons to previous fitment is irrelevant.
You still didn't mention what engine mounts you used, the one picture that showed the DS mount looks like an aftermarket bracket- are you sure you ordered or recieved the correct ones?
You can also try jacking up/hoisting the engine another half-3/4 of an inch off of the pedestals to see if that improves your clearances. If so, either shim your mounts or install the thicker 1980ish truck mounts (about $5, a heckuva lot cheaper than a tubular K frame).
SKM2469(1)__ra_t.jpg

And make sure your mounts are situated all the way to the passenger side, the pedestals are slotted and allow you some degree of adjustability.
 
Motor mount "looks" a little old. But seems like you need to move away more than just one replacement mount.

I believe they make a truck mount that is thicker. But looks like you're going to need a dimple.

I don't think its cost effective to buy a new K-member purely to take a chance that it solves this ? 1/2" clearance issue. The money, time, effort just to bank on 1/2 quality control (dimensional stack up) is too risky.

Not that is bad, but looks like there is an repro motor mount bracket used. Just another variable.

View attachment 1715958561
 
Motor mount "looks" a little old. But seems like you need to move away more than just one replacement mount.

I believe they make a truck mount that is thicker. But looks like you're going to need a dimple.

I don't think its cost effective to buy a new K-member purely to take a chance that it solves this ? 1/2" clearance issue. The money, time, effort just to bank on 1/2 quality control (dimensional stack up) is too risky.

Not that is bad, but looks like there is an repro motor mount bracket used. Just another variable.

View attachment 1715958561
Ya treed me. I'm old, I type slow... :)
 
I'm thinking of converting to a tubular k frame from a stock one not sure how strait my original is. And I'm having issues with header fitment and stearing box hitting headers that I didn't have before also I'm converting to a 360 from a 273 any help is appreciated
Check out @HemiDenny he is on FABO pretty regular. Can’t go wrong with his product. I have been thrashing on his work for years and still can’t break it! Hah!
 
Anyone have a measurement of how much thicker a new truck mount is from a new OE type mount?
 
Anyone have a measurement of how much thicker a new truck mount is from a new OE type mount?
Just went out to the shop and measured- the pass car mount is 1" thick, the truck mount is 1.5".
The diesel mount, which will also work, is a bit thicker than the regular truck mount- exactly how much, I don't know; I didn't have one of those to measure at the moment.
 
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