72 K30 Build

[7dee2]

Originally Posted by DLTruck1973

Hi Brett,

It was a pleasure to meet you.Tom and I are glad that you could come here and check out a small portion of the inventory

It is always nice to be able to help out everyone with needed parts. Looking forward to seeing your progress on the project as well.

Thank you again for everything,
Thomas

Thanks Thomas you guys are the best! Sure I'll be talking to you soon.

Originally Posted by coops714x4

HOORAY, now the fun begins, Brett in this part of your build I would really appreciate some real good measurements and info in changing the C/30 frame to K/30, like I told you I have a chassis and considering doing the same thing, it would really be helpful. good luck, Coop< got my glasses on and notepad handy pencil in hand.

No problem Coop! We know how to have a good time around here!

[7dee2]

We are still in the process of harvesting axles/steering/hangers/springs/mounts & cross members from the K3500 since I don’t know for sure what we or somebody else may want or need. I know we gotta git rid of this 4x limo frame and the C30 nubby that I’ve decided not to use so we’ve got some room.

[rs74]

Subscribed! I would like to build one of these too. I have had the thought of either trying to get my father in laws 67 GMC C35 he bought new or get another C30 and build one of these. I have followed JJorgensen52's build also. My initial questions were would I do a K20 frame or mod the C30 frame. Seems like the C30 are a bit more beefy than K20. Although it might be easier for the front axle swap on the K20 but then would have to do something about the inboard mounting on the rear axle for shocks.

I have had a couple 84, 85 and now an 86 GMC K35 and have always wanted a 67-72 style. That is all I can remember my grandpa driving when I was growing up. My thoughts are a possible flat bed with dump and put a plow on the front and just use for my hauling/towing needs with occasional plowing unless I get something else to plow with(just for my personal needs). Going for a look like the following members picture. Would have to say goodbye to my 86 if I go this route.

Looks like you are starting to get things figured out now. Looking forward to your progress.

[7dee2]

Originally Posted by rs74

Subscribed! I would like to build one of these too. I have had the thought of either trying to get my father in laws 67 GMC C35 he bought new or get another C30 and build one of these. I have followed JJorgensen52's build also. My initial questions were would I do a K20 frame or mod the C30 frame. Seems like the C30 are a bit more beefy than K20. Although it might be easier for the front axle swap on the K20 but then would have to do something about the inboard mounting on the rear axle for shocks.

I have had a couple 84, 85 and now an 86 GMC K35 and have always wanted a 67-72 style. That is all I can remember my grandpa driving when I was growing up. My thoughts are a possible flat bed with dump and put a plow on the front and just use for my hauling/towing needs with occasional plowing unless I get something else to plow with(just for my personal needs). Going for a look like the following members picture. Would have to say goodbye to my 86 if I go this route.

Looks like you are starting to get things figured out now. Looking forward to your progress.

What a great looking truck Roy that's one of my favorites, love the blue & white combo. Here is another pic of that same truck I had saved, I'm not 100% but I could swear I read this is a 3/4 ton with drw adaptors?

I think this white one is also a 127" wb truck?

[7dee2]

Parts & pieces, getting ready to start slicing this frame up like a pizza!

[7dee2]

Here's some smoky pics and a frame cake!

[Dieselwrencher]

Do you plan to keep the spring hangers from this frame?

[7dee2]

Originally Posted by Dieselwrencher

Do you plan to keep the spring hangers from this frame?

That's good question Mr. Wrencher, RedRoad (Tony) pm'd me a couple of weeks ago and was also curious about some K3500 stuff. I'm still not 100% sure what we're going to use so for now I'm harvesting/collecting parts and hanging onto everything. I'll put you second in line if you would like?

[7dee2]

Suspension/chassis options for this Longhorn to K30 Big Block conversion.
Our goals are keeping a low ride height, factory look and we do not want to modify the firewall for clearance. Doing it right the first time and not having to redo anything priceless!

What would be the general consensus on engine mount and front & rear spring hangers?

Additional info:
Longhorn 133” frame, K3500 CC dually chassis parts donor
Torquey 454/496 (TBD) mounted in forward 2wd position running stock exhaust manifolds
T 400 w/205 transfer case (w/possible GV overdrive?)
D60 & CC 14Bolt DRW axles

Here are some of our options:

Front option #1
Complete 67-72 K1, 2 setup (motor cross member may need to be modified for frame fitment, BB pan & front pumpkin clearance?). You couldn’t look more factory than this so it’s high on my list but might not be practical due to clearance issues.

Front option #2
Complete K3500 mounts (clamshell style motor mounts will need to be reworked to fit the Longhorn frame) cross members & hangers complete.

Front option #3
Combination of option’s 1 & 2
Use the K3500 motor mounts/cross member with K1,2 front spring hangers.

Front option #4
I’ve got a 73 only (according to GM parts book) set of mounts (clamshell style) w/cross member (not as heavy duty as the K3500 stuff). We also have some front spring hangers that I was told came from the same application and they are a little different than the later square bodies.

All front options will include adding the front sway bar from the K3500. We’re going to need new front springs. The only front springs we have are from the K3500 and are too long for this build. Also we want to use the factory automatic linkage, so thinking 67-72 length front springs and hangers are a must to leave room for the frame mounted linkage pivot (mounts left side rail close to the front rear hanger and front body mount on that side (I have both T400 & T350 pivot styles))? Also we do have both a 67-72 and the later square body style trans/transfer case mount. I’m a little concerned about the additional weight a GV overdrive might create. Wondering if a 205 right side bracket might help with this? Thinking some would suggest we go with a 4l80e and a standalone controller. This was my thoughts originally as well, we even acquired a core trans from forum member mjensen. As this build project got closer I remembered how many newer OD type transmissions I’ve smoked in the past.


Rear option #1
Complete 71-72 K1,2 hangers w/new springs.

Rear option #2
Complete K3500 springs & hangers. JJorgensen52 did this in his 72 GMC K30 build and it looked like it worked quite well.

Rear option #3
Complete C30 springs and hangers. Pretty sure we have enough parts left over from the motor home chassis to pull this off. We would need to use additional blocks to get the ride height level.

Either rear option 2 or 3 we have spring packs that can be refurbished and shouldn’t need new rear springs.

[JJorgensen52]

Originally Posted by 7dee2

Suspension/chassis options for this Longhorn to K30 Big Block conversion.

The biggest problem I ran into with trying to keep the motor low in the chassis for firewall clearance was the PS pump setup on the '67-'72 style brackets does not clear the later 4WD style cross members. I had to notch it to let the pump sit down into the cross member.

As for ride height - I really don' think you can go any lower than the way my build was, in the front. There's just not enough room to clear the suspension up front. The D60 front axle is TALL and even if you bolted it onto a K10 it would still be about 2" of lift just from that, nevermind the tires.

[7dee2]

Originally Posted by JJorgensen52

The biggest problem I ran into with trying to keep the motor low in the chassis for firewall clearance was the PS pump setup on the '67-'72 style brackets does not clear the later 4WD style cross members. I had to notch it to let the pump sit down into the cross member.

As for ride height - I really don' think you can go any lower than the way my build was, in the front. There's just not enough room to clear the suspension up front. The D60 front axle is TALL and even if you bolted it onto a K10 it would still be about 2" of lift just from that, nevermind the tires.

I remember reading the power steering pump clearance issue you had. I'm sure we will probably run into the exact same thing using the square body motor mounts & cross member. We did keep the pump and brackets off the K3500 so maybe that will help?

I'm aware the D60 is tall and am trying to keep my build as low as yours is. We are thinking we could live with that height just fine!

[JJorgensen52]

Originally Posted by 7dee2

I remember reading the power steering pump clearance issue you had. I'm sure we will probably run into the exact same thing using the square body motor mounts & cross member. We did keep the pump and brackets off the K3500 so maybe that will help?

I'm aware the D60 is tall and am trying to keep my build as low as yours is. We are thinking we could live with that height just fine!

Yes those brackets will definitely help. On those late trucks the PS pump is pulled up and out about 3" from where it sat in the '67-'72s, basically in the same position they used for the later serpentine setups as well. You could install the original style pump in those brackets and nobody but a real stickler would know the difference

[7dee2]

Originally Posted by JJorgensen52

Yes those brackets will definitely help. On those late trucks the PS pump is pulled up and out about 3" from where it sat in the '67-'72s, basically in the same position they used for the later serpentine setups as well. You could install the original style pump in those brackets and nobody but a real stickler would know the difference

Thanks, gonna try that good idea!

Here is some more progress tearing down the K3500 frame.

[7dee2]

Still need to harvest the rest of the hangers and such but we've got some room for the Longhorn frame now!

[JJorgensen52]

Originally Posted by 7dee2

Still need to harvest the rest of the hangers and such but we've got some room for the Longhorn frame now!

Nice! I got about nothing done this weekend on my '50, I need to get motivated

Your picture of the axles reminds me. The worst part of the WHOLE build was bleeding those darn rear brakes ... so hard to get to the bleed screw on the narrow 14FF

[7dee2]

Originally Posted by JJorgensen52

Nice! I got about nothing done this weekend on my '50, I need to get motivated

Your picture of the axles reminds me. The worst part of the WHOLE build was bleeding those darn rear brakes ... so hard to get to the bleed screw on the narrow 14FF

You, you slacker!! Did that help? Thanks for the warning I didn't know it was that tight. Did you figure out any tricks or was it just a suffer through?


So here it is in all it's beauty!

[JJorgensen52]

Originally Posted by 7dee2

You, you slacker!! Did that help? Thanks for the warning I didn't know it was that tight. Did you figure out any tricks or was it just a suffer through?


So here it is in all it's beauty!

Of course

That's a nice looking donor!

I think GM makes a special long bleed wrench to reach down in there next to the spring packs, but I did not have one. I was able to get down in there with a regular open end wrench with some effort, but it took forever!

[7dee2]

Originally Posted by JJorgensen52

Of course

That's a nice looking donor!

I think GM makes a special long bleed wrench to reach down in there next to the spring packs, but I did not have one. I was able to get down in there with a regular open end wrench with some effort, but it took forever!

Thanks, your GMC cab is really looking great sir! My wife keeps telling me I'm building the wrong body style!

Brought what's left of the old motorhome chassis into the kill zone! I now have a very wide variety of factory mounts, hangers and such.

[7dee2]

Another box showed up from DLTruck1973 it's the rest of a K20 hanger/bracket/mount donor! With what we already have we should be able to nail the ride height exactly were we want it. Thanks Tom & Thomas you guys are the best!!

[DLTruck1973]

Originally Posted by 7dee2

Another box showed up from DLTruck1973 it's the rest of a K20 hanger/bracket/mount donor! With what we already have we should be able to nail the ride height exactly were we want it. Thanks Tom & Thomas you guys are the best!!

Hi Brett,

Always glad to help when we can. Keep up the good work. Looking forward to seeing progress moving forward.

Take care,
Thomas

[7dee2]

Started prepping the longhorn frame for the 2wd to 4x4 conversion.

[JJorgensen52]

Originally Posted by 7dee2

Started prepping the longhorn frame for the 2wd to 4x4 conversion.

Just looking at your photo - did you save the front upper shock mount re-enforcement tab? It was held on with two rivets. You can buy them from some of the vendors if you did not. Highly suggest installing that with through bolts like a factory 4x4.

[7dee2]

Originally Posted by JJorgensen52

Just looking at your photo - did you save the front upper shock mount re-enforcement tab? It was held on with two rivets. You can buy them from some of the vendors if you did not. Highly suggest installing that with through bolts like a factory 4x4.

Yep, I've still got the K3500's brackets and was planning on running those.

[7dee2]

Huh, the factory 4x motor cross member sure is a tight fit. Doesn’t get anywhere near the 2wd position without some trimming or a lot of force? I know they set the motor back but, wow...

[JJorgensen52]

Originally Posted by 7dee2

Huh, the factory 4x motor cross member sure is a tight fit. Doesn’t get anywhere near the 2wd position without some trimming or a lot of force? I know they set the motor back but, wow...

It's been a while since the motor was out of my K10, but are you sure that's not backwards?? I seem to recall it curving forward rather than back.

Also, you might try taking the upper braces off, and see if just the lower portion will fit.