What would it take to fit Q78 tires on a stock 66 K10 4x4?

[fishmunger]

Hey gang,

I’m considering purchasing a 66 K10 4x4 longbed with an original drivetrain. It would be a running project type truck. Rough around the edges. Goal would be a patina’d part time work\daily type truck. I used to have a slammed 64, been wanting one of these in a 4x4 for a few years now.

I think these trucks look perfect to my eye with Interco swamper Q78 tires. They are tall (35.5”) but skinny (10.5”). Do you think these tires would fit under an original 66 k10 (the truck currently sits on wagon wheels with 33x12.5 but I have no idea if it rubs or not.

I’ve done some research and understand no one makes a bolt in lift kit for these trucks if I end up needing to lift it a bit. I don’t want to swap the drivetrain out for a later gen either. Is there a way I could make this work for not too much effort and $$$ (a couple days labor and less than $800 tops) or is this a pipe dream?

[b454rat]

I had a 62 burb 4x4 that had 35s on it when I bought it. It didn't look bad, but did have the stuffed looked. I'd think even they are skinny, the Q78s would hit somewhere. You could get a set of zero rates, but they only give you an inch...

[74CustomK20]

If you do have to lift it, finding what axle you have will help your steering parts, but atlas or maybe order, bds can make lift sorongsytgat ride better than new.

[TwoFiftyShifter]

Cmon dude. That is a huge tire for a stick size truck. If you hit a pothole, might rip a fender off.

[k14burb]

I think they might fit stock depending on your wheel offset. My '66 had 2" blocks in the front (to clear the BB oil pan) and 1" blocks stacked on the back with 35x12.50 15's when I bought it. (I don't know how much lower the 454 and accessories made it sit vs. the original small block with no AC or power anything)

First thing I did was take it to a spring shop and had them build me a new front spring pack (with like an extra inch, so 3ish total) and ditch the front blocks. Since I had a set of 37x12.50 17 take offs sitting there, I tried them and they fit with slight rubbing in the rear when crossed up or dumping the clutch in low gear due to axle wrap. This generation of 4x4 sits pretty high and has tons of front fender clearance. That narrow of tire should clear the rear okay with proper offset. Below, 3" lift in front, 1" rear with old school 37x12.50 17 BFG Mudders on 17x8 slotts with 0 offset, and the rear would rub a bit if off roaded aggressively.

['63GENIII]

Ive had my 35" BFG MTs (which I think are 34.5") on this truck since I swapped to the 3/4 ton axles. Stock suspension though. Only place it rubbed was on the front of the rear fender when loaded really heavy. Think 1-1/2 pallets of 60# concrete sacks. I think it was around 3800# in the bed.

Now with the spring swap, it will sag a bunch more under load (in the rear) but I used spring perches on the rear axle that allowed me to move the axle back 1". No more rubbing anywhere.

Since Im running 16.5 x 9" wheels and will be needing new tires soon, Ive thought about running some of the Humvee takeoffs which are 37" IIRC. I think these may push the limits of the clearance that I have but I may be able to get away with it.

Im almost certain I can run a skinny 35 now and could have when the truck was stock.

First pic is unloaded in the driveway. Stock suspension - BFG 35s. You can notice that the rear wheel is closer to the front lower edge of the rear fender. IIRC the multi position spring perches were 50 - 60$ from Summit. This suspension doesn't compress much at all. Even loaded.

Second pic is a half unloaded bed of boulders from around Thanksgiving last year 2018. No rubbing even with near 3k in the bed on the newer suspension.

[k14burb]

Originally Posted by '63GENIII

Ive had my 35" BFG MTs (which I think are 34.5") on this truck since I swapped to the 3/4 ton axles. Stock suspension though. Only place it rubbed was on the front of the rear fender when loaded really heavy. Think 1-1/2 pallets of 60# concrete sacks. I think it was around 3800# in the bed.

Now with the spring swap, it will sag a bunch more under load (in the rear) but I used spring perches on the rear axle that allowed me to move the axle back 1". No more rubbing anywhere.

Since Im running 16.5 x 9" wheels and will be needing new tires soon, Ive thought about running some of the Humvee takeoffs which are 37" IIRC. I think these may push the limits of the clearance that I have but I may be able to get away with it.

Im almost certain I can run a skinny 35 now and could have when the truck was stock.

First pic is unloaded in the driveway. Stock suspension - BFG 35s. You can notice that the rear wheel is closer to the front lower edge of the rear fender. IIRC the multi position spring perches were 50 - 60$ from Summit. This suspension doesn't compress much at all. Even loaded.

Second pic is a half unloaded bed of boulders from around Thanksgiving last year 2018. No rubbing even with near 3k in the bed on the newer suspension.

Wow, how did I miss your build threads? Tons of great info! Thanks!!!

I’ve got Dana 60’s under my rig now with an Lq4/4L80e, but need to do something about the springs and get the t221 swapped with the divorced 205 that’s been sitting in the corner for a decade. Can’t kill the 221. Don’t want to hijack this thread, but you’ve given me lots to study.

['63GENIII]

Originally Posted by k14burb

Wow, how did I miss your build threads? Tons of great info! Thanks!!!

I’ve got Dana 60’s under my rig now with an Lq4/4L80e, but need to do something about the springs and get the t221 swapped with the divorced 205 that’s been sitting in the corner for a decade. Can’t kill the 221. Don’t want to hijack this thread, but you’ve given me lots to study.

I gotta say, that Burb is super nice looking. If you have any questions on the springs and 221 swap, just ping me on one of the build threads.

One thing that I really like about these trucks is like you said, "This generation's of trucks sits up pretty high and has a lot of fender clearance". Very true. Didn't take a whole lot of work to fit the tires under them. Also helps with the low gearing of the 60s and 14BFF axles!

Cheers!

[fishmunger]

wow, thanks so much for the pics and info!! I had a feeling these trucks could take a lot in stock form. I was hoping that with the Q78s being so skinny would do the trick.

Both the burb and big orange are such badass looking rigs. love 'em

[argonaut]

I agree in that I believe the Q78 tires will fit. Stock 60-66 4x4 pickups were significantly higher than later model 4x4s.

[1976gmc20]

Originally Posted by argonaut

I agree in that I believe the Q78 tires will fit. Stock 60-66 4x4 pickups were significantly higher than later model 4x4s.

The funny [strange] thing is that back then those tall 4x4 pickups were considered something of a disadvantage, and even an embarrassment.

The Jeep Gladiator used to be advertised as having the same cab and bed height as a regular pickup, until ~1967 when GM started making their 4x4's a bit lower, and Ford not until sometime up in the late 1970s (?). Dodge was somewhere in the middle I think.

NOW, you can't hardly tell a new 4wd from a new 2wd pickup, except for stickers. And nearly everyone wants to spend a fortune to jack them up to about where they used to be at factory height.

[k14burb]

Originally Posted by 1976gmc20

The funny [strange] thing is that back then those tall 4x4 pickups were considered something of a disadvantage, and even an embarrassment.

The Jeep Gladiator used to be advertised as having the same cab and bed height as a regular pickup, until ~1967 when GM started making their 4x4's a bit lower, and Ford not until sometime up in the late 1970s (?). Dodge was somewhere in the middle I think.

NOW, you can't hardly tell a new 4wd from a new 2wd pickup, except for stickers. And nearly everyone wants to spend a fortune to jack them up to about where they used to be at factory height.

First trip I took my new at the time 2012 Z71 4x4 off road, I tore off the ridiculously low air dam less than 1/4 mile down a very mild trail an older bone stock 2wd would have no problem with.

[1976gmc20]

Originally Posted by k14burb

First trip I took my new at the time 2012 Z71 4x4 off road, I tore off the ridiculously low air dam less than 1/4 mile down a very mild trail an older bone stock 2wd would have no problem with.

The sooner you got rid of it, the better

Some of these new pickups look like they have less ground clearance and worse approach/breakover/departure angles than a 1969 Impala.

[k14burb]

Much better approach angle now.

[1976gmc20]

Originally Posted by k14burb

Much better approach angle now.

Did you cut that bumper lengthwise or replace it ???

[k14burb]

Originally Posted by 1976gmc20

Did you cut that bumper lengthwise or replace it ???

It’s just a fiberglass cover.
http://www.socalsupertrucks.com/2007...x#.XLnYmoplCf0

[1976gmc20]

Originally Posted by k14burb

It’s just a fiberglass cover.
http://www.socalsupertrucks.com/2007...x#.XLnYmoplCf0

So is there a steel bumper under that? I don't know much about these newer trucks.

Why not just an all steel aftermarket bumper or winch bumper? I suppose that would be a lot more than $300.

I just recently took the under bumper wind deflector off my 89. It wasn't dragging or anything but it made it hard/impossible to use the tow hooks with an eye splice tow strap/cable. Plus it's easier to work on now and looks more like a truck!

BTW, I love those old 60-66 pickups. My friend down in CO has a 1966 K-20 with a 292-6 that he uses for firewood. I did a ring job on that truck back in the 1980s after his dad let it run low on oil. They used to use it for feeding cows and it would start every morning at -40 without an engine heater.

[k14burb]

Originally Posted by 1976gmc20

So is there a steel bumper under that? I don't know much about these newer trucks.

Why not just an all steel aftermarket bumper or winch bumper? I suppose that would be a lot more than $300.

I just recently took the under bumper wind deflector off my 89. It wasn't dragging or anything but it made it hard/impossible to use the tow hooks with an eye splice tow strap/cable. Plus it's easier to work on now and looks more like a truck!

BTW, I love those old 60-66 pickups. My friend down in CO has a 1966 K-20 with a 292-6 that he uses for firewood. I did a ring job on that truck back in the 1980s after his dad let it run low on oil. They used to use it for feeding cows and it would start every morning at -40 without an engine heater.

Yeah, the steel bumper is underneath and you’re right, if I had to do it again I’d just get a steel fab bumper.

Back to the topic at hand, here’s the ‘66 with the newer axles and 315/70 17’s which are pretty wide.


I like the skinnier looking 37x12.50’s better. (I do like the steel Dodge rims better though)

[1976gmc20]

Yep, I like the tall skinny tires on those old trucks. They served us well back in The Day.

Why drive over a rock if you can drive around?