72 K30 Build

[DLTruck1973]

Originally Posted by 7dee2

So Big Kudos to D & L Truck Parts out of Junction City, OR forum vendor “DLTruck1973” Tom & Thomas they have fixed us up big time!

First we ordered 71/72 K20 front spring hangers, shackles, front bump stops & outer bumper brackets, both engine & trans/transfer case cross members (next best thing to a K20 donor). These parts arrived very quickly and are practically like new, hot tanked and packaged with care it was like Christmas opening the box. My thoughts were we can use these parts and do mockup on my C30 frame nub while the frame search continued. But in some of my correspondence with Thomas I asked about a C30/Longhorn frame. These guys have everything I swear and go the extra mile! Once they were sure we were serious and could arrange shipping they brought in a Longhorn and processed it so we could get the frame we needed!

WOW! ROAD TRIP, YES!!



What a great facility they have there, it was like 67-72 heaven, we got to fill our short list plus some other goodies I couldn’t resist and have been looking for for years. I just can’t thank these guys enough it really gave this project a shot in the arm so very impressed with them!

Second picture is somewhere in Idaho on the way home.

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

[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.

[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?

[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!

[Dieselwrencher]

Man, you need a proper hammer for knocking those rivets off and out. The air type one works wonders!

[7dee2]

Originally Posted by Dieselwrencher

Man, you need a proper hammer for knocking those rivets off and out. The air type one works wonders!

Ha Big D, you mean we can’t get it wit deez? Dem flippin nails keep a bend’n!

[7dee2]

Originally Posted by DWilbur

Dieselwrencher check out picture 3 he has a single jack. I smacked my hand several time before I got smart and held the punch with a pair of vise grips to pound out the rivets.

I’m thinking the use of vise grips to hold the punch is some really good advice. Not that smart around here though but glad to report no busted knuckles this round.

Originally Posted by DLTruck1973

If possible Brett, put some heat on them brackets around the rivet. They will practically fall out with not much effort at all.

Looking forward to the roller

You know I've got an air hammer and some ear plugs but honestly they were popping out pretty easily with what we were using. So we didn’t need to bring the heat but I’m sure that would work really, really well. A couple of good smacks per rivet with my little friend is all it took.

Wish we could have found my very favorite 5 lb. shorty sledge for this round, it’s currently MIA!

Removed some old remnants of the welded on rear bumper brackets. Still need to lose the original rear spring hangers as I’m sure trying to use them would make the truck way to low in the back.

[JJorgensen52]

Originally Posted by 7dee2

Removed some old remnants of the welded on rear bumper brackets. Still need to lose the original rear spring hangers as I’m sure trying to use them would make the truck way to low in the back.

I love it when people weld things to their truck frame

What springs are you using in the rear?

[7dee2]

Yep me too! Sure seems to have been popular back in the day.

Todays plan is to use the K3500 spring pack. Don’t really want to use any blocks like the pic below. So for now it looks like the K1, 2 front hangers with the K3500 spring packs (need to remove 2 add a leafs per side). Rear hangers will probably be K3500 also, TBD by ride height with the front end loaded up.


There is quite a bit of difference in most of the rear hangers. Since receiving the shipment of K1, 2 rear hangers from DLTruck1973. I found out that both the K1, 2 and my 72 C30’s rear hangers are all the same. I’ve got 2 sets of these now, oops. The Longhorn frame has some earlier cast style w/grease able pins (cool) that I probably won’t be using. The K3500 rear hanger set is probably the most HD and will yield the most lift.

[DWilbur]

Dieselwrencher check out picture 3 he has a single jack. I smacked my hand several time before I got smart and held the punch with a pair of vise grips to pound out the rivets.

[First c10]

Hey Brett great build. I will be keeping up on your build. I maybe using a 2wd frame as well. If you have a set of rear hangers you want to get ride of let me know.
I am building a k10 lwb '68 with and for my son. Keep up the updates we all appreciate it.

[7dee2]

Originally Posted by JJorgensen52

You don't happen to have the greasable shackles do you? Those are unique to '67 and not reproduced.

A lot of the lift in the rear comes from the front hangars in these trucks, they drop the front eye down a solid 2.5" - I would be cautious mixing and matching them, might mess with your driveline angles.

No I don’t, but if it had the greaseable shackles then D & L Truck (DLTruck1973) would have them those guys have got everything I swear!

I agree on what you’re saying about the driveline/pinion angles and think that is pretty good advice. The K3500 rear position rear hangers maybe a must to maintain the angle without a correcting shim. It will be interesting to see were we end up after mocking up the front end.

Originally Posted by 71blksuper4x4

On my crew with the cab & chassis frame, the frame is straight from the kick up back. After spending about a week researching and thinking it through, I am using the 73-87 3/4 ton spring hangers. Since I am using the the AAM 11.5 rear I have to relocate my axle perches anyway so gaining an inch in width on how far out the hangers sit won't bother me. (5.5 " out from frame vs 67-72 4x4 4.5" and 73-91 k30) I think your best bet is to use the k30 hangers personally. They will fill the frame rail closer as the 67-72 style only filled half of my modulus portion of frame. JMO. I needed the longest drop hanger I could find to match how much taller my frame is compared to the longhorn style frame rear. The duramax furthest rear hanger is about an inch lower 10" to the 73-87 k20 9". 67-72 furthest rear is 6" drop. The duramax ones can't be used as they are 4" out in front hangers and 5" out on back ones to account for the frame overlapping they do on the new frame rails. Just trying to help as I have been there and weighed all options out.

This is great info Trevor thanks! Below are few more pics for thought on this 67-72 K20 to next gen K30 rear hanger comparisons.

I was surprised how different the Longhorn/CC 133 “ vs. CC 157” frame rails really are from the transmission mount rearward. It becomes very obvious why the CC 157" is the strongest frame in the series.

Originally Posted by First c10

Hey Brett great build. I will be keeping up on your build. I maybe using a 2wd frame as well. If you have a set of rear hangers you want to get ride of let me know.
I am building a k10 lwb '68 with and for my son. Keep up the updates we all appreciate it.

Thanks First c10 I appreciate your kind words and will keep you in mind, thanks. Building stuff with your kids is the best and "The Hulk" is going to be a beast!

[7dee2]

Some parts arrived, poly cab mount & front spring bushing kits. New 67-72 K20 springs showed up also. All those stickers you would think those springs came from Chumbawamba not Kansas City!

Don't want to lose the 1 ton capacity so we will start with these springs and then add a leaf if needed when the truck is done.

[7dee2]

Good news is I know why the 67-72 K1, 2 engine cross member did not fit as I would have liked. So I tried it in my 72 C30 RV front frame nub. Slide right up to the front mounting holes no problem, so why not the Longhorn was my question??

Bad news is the Longhorn frame we acquired is tweaked a little bit. Not a big surprise from a 45+ year old truck frame.

[7dee2]

Looking at this more closely with a tape found the majority of the frame seems to be square. Not so much from the front cab mount area going forward it hooks to the left side.

Left rail was twisted inward right about ½” at the top where the engine crossmember goes, and then it continues kicking out left going forward. Right rail looks perfect but does bend gradually to the left no twist found. You can kind of see it in these comparison pics.

[Dieselwrencher]

You might be able to use a long bar/tube chained to the frame rail and twist it back. Sometimes these frames have pre load in them from being sprung or what have ya, and they will try to go back to their original formed state. And on your pinion angle, that is a easy fix. Cut the original spring perch welds on the diff housing. Set your pinion angle, and re weld.

[7dee2]

Originally Posted by Dieselwrencher

You might be able to use a long bar/tube chained to the frame rail and twist it back. Sometimes these frames have pre load in them from being sprung or what have ya, and they will try to go back to their original formed state. And on your pinion angle, that is a easy fix. Cut the original spring perch welds on the diff housing. Set your pinion angle, and re weld.

Really kind of surprising at how easily the steel moves. Also found none of our bottle jacks liked to work laying on their side horizontally need to be vertical, must be a gravity thing.

So put a laser down both rails and found both rails hook to the left by around a 1” or so each. Hoped to straighten it ourselves and we have been partially successful these last few days. Got the twist out of the left rail (cross member fits now), also got a little movement on the left front horn back to the right. Not much luck with the right rail and not enough on the left is how it sits now.

[JJorgensen52]

Originally Posted by 7dee2

Really kind of surprising at how easily the steel moves. Also found none of our bottle jacks liked to work laying on their side horizontally need to be vertical, must be a gravity thing.

So put a laser down both rails and found both rails hook to the left by around a 1” or so each. Hoped to straighten it ourselves and we have been partially successful these last few days. Got the twist out of the left rail (cross member fits now), also got a little movement on the left front horn back to the right. Not much luck with the right rail and not enough on the left is how it sits now.

I like it!

Is there any hook in the frame behind the front cross member? I was just looking at one with a bend in it the other day, and after some careful checking the bend was actually way back at the front cab mount.