How To: Ruin a Perfectly Good 4wd

[whitesilverado]

Mine in the works

[Bennett68C10]

I’m in for this build for sure, to answer your question on your other thread, I really like the TTII’s I have. The only problem I’m having is with the backspacing on the rear wheels and my narrow rear axle I’m running in the burb. They don’t fit at all without running a wheel spacer or adapter which I’m not a fan of. Trying to figure out what I want to do about it now.

[gringoloco]

Originally Posted by sprint_9

Awesome, Im excited to see this come together, I kind of want to do a blazer myself sometime.

If it’s anything like your truck, should be nice!

Originally Posted by whitesilverado

Your going to be using very nice product. Mine coming out good.

Looking good! Any issues so far? Build thread?

Originally Posted by Bennett68C10

I’m in for this build for sure, to answer your question on your other thread, I really like the TTII’s I have. The only problem I’m having is with the backspacing on the rear wheels and my narrow rear axle I’m running in the burb. They don’t fit at all without running a wheel spacer or adapter which I’m not a fan of. Trying to figure out what I want to do about it now.

Too bad you’re not closer, we could work something out. I could use a narrow axle for my truck...

[C10_ustacould]

Originally Posted by gringoloco

I’ll take that as a compliment

Yep

[aggie91]

In for the ride too. I have always had a spot for these blazers, especially the 2wd versions. The DEG parts look good.

[lolife99]

Great thread!
The only thing I would add to the Deadend Garage parts,... is a 2" lowering block to help keep your ride height low,... with the correct pressure in the air bags.
I'm glad to see someone document a 4x4-to-2wd conversion with Deadend Garage parts.

[lolife99]

Originally Posted by Bennett68C10

I’m in for this build for sure, to answer your question on your other thread, I really like the TTII’s I have. The only problem I’m having is with the backspacing on the rear wheels and my narrow rear axle I’m running in the burb. They don’t fit at all without running a wheel spacer or adapter which I’m not a fan of. Trying to figure out what I want to do about it now.

Keith,... which Torq Thrusts did you order?
The 1-piece VN515 or the 2-piece VN405 wheels?

The 1-piece wheels are cheaper but only come in set backspaces.
20x8 (4.5"bs) and 20x10 (5.75" bs)

The 2-piece wheel comes in 20x8, 20x9.5, 20x10, 20x12, and 20x15 with a large variety of backspaces.

When I ordered mine for my blazer I specified the backspace I wanted, since they were going through the custom shop anyway.

[fatbass]

I hope you realize that converting a 4X4 to 2WD in Utah is a felony.

J/K- I subbed now.

[Bennett68C10]

Originally Posted by lolife99

Keith,... which Torq Thrusts did you order?
The 1-piece VN515 or the 2-piece VN405 wheels?

The 1-piece wheels are cheaper but only come in set backspaces.
20x8 (4.5"bs) and 20x10 (5.75" bs)

The 2-piece wheel comes in 20x8, 20x9.5, 20x10, 20x12, and 20x15 with a large variety of backspaces.

When I ordered mine for my blazer I specified the backspace I wanted, since they were going through the custom shop anyway.

My TTII’s are the 1-piece VN515 that I had on my 68! The backspacing worked on that truck because it laid frame and was going to have a modified bed floor and wheel wells. The 5.75” backspacing on the 1-piece 20x10’s absolutely do not work on my 66 Burb with the narrow rear I’m using without an adapter and I’m not interested in cutting into the Burb to make them fit. I also don’t want to change out my rear as I have a good amount of $ tied up into rebuilding it. After doing some thorough measuring over the weekend, I solved my problem yesterday when I ordered 2 20x10 VN405 2 piece polished TTII’s from Travis at Pro Performance. I really liked the look of the TTII’s on my Burb so I just ordered a pair with the exact backspacing I needed. They should match up close enough to the front 1-piece wheels that no one should be able to notice a difference. I’ll be putting the 2 1-piece 20x10’s up for sale after I get the new wheels.

[lolife99]

Originally Posted by Bennett68C10

My TTII’s are the 1-piece VN515 that I had on my 68! The backspacing worked on that truck because it laid frame and was going to have a modified bed floor and wheel wells. The 5.75” backspacing on the 1-piece 20x10’s absolutely do not work on my 66 Burb with the narrow rear I’m using without an adapter and I’m not interested in cutting into the Burb to make them fit. I also don’t want to change out my rear as I have a good amount of $ tied up into rebuilding it. After doing some thorough measuring over the weekend, I solved my problem yesterday when I ordered 2 20x10 VN405 2 piece polished TTII’s from Travis at Pro Performance. I really liked the look of the TTII’s on my Burb so I just ordered a pair with the exact backspacing I needed. They should match up close enough to the front 1-piece wheels that no one should be able to notice a difference. I’ll be putting the 2 1-piece 20x10’s up for sale after I get the new wheels.

Good to hear. I was afraid you were going to change to a different wheel.
Those look so good on your suburban!


Sorry for hijacking your thread gringoloco.

[gringoloco]

Originally Posted by aggie91

In for the ride too. I have always had a spot for these blazers, especially the 2wd versions. The DEG parts look good.

They do look nice. Ready to get my hands on them

Originally Posted by lolife99

Great thread!
The only thing I would add to the Deadend Garage parts,... is a 2" lowering block to help keep your ride height low,... with the correct pressure in the air bags.
I'm glad to see someone document a 4x4-to-2wd conversion with Deadend Garage parts.

If I bag it, it will definitely get 2” blocks. Right now, probably going static, as I have most of the parts on hand... unless I can find another $2-3k in the budget to bag it properly.

I’ve been wanting to document a conversion for a while now; I’m personally more interested in properly locating the front crossmember for prosperity, as there seems to be lots who have done it, but no definitive guidance. The DEG parts should make the rear a snap; remains to be seen!

Originally Posted by fatbass

I hope you realize that converting a 4X4 to 2WD in Utah is a felony.

J/K- I subbed now.

Yes, everyone that my wife has mentioned this to at her work thinks I’m a lunatic and won’t talk to me anymore... I’ll just go over here and be crazy by myself

Originally Posted by Bennett68C10

...I’ll be putting the 2 1-piece 20x10’s up for sale after I get the new wheels.

PM sent.

Originally Posted by lolife99

...Sorry for hijacking your thread gringoloco.

No worries, it’s part of why we do this

[knomadd]

Dang, a few days away and I've missed a lot of conversation. Your plan sounds great! I'll be following along.

[lolife99]

Originally Posted by gringoloco

I’ve been wanting to document a conversion for a while now;
I’m personally more interested in properly locating the front crossmember for prosperity, as there seems to be lots who have done it, but no definitive guidance.
The DEG parts should make the rear a snap; remains to be seen!

:

Funny you mention that.
I've always thought about these conversions in great depth.
For me personally,... I would move the entire crossmember forward 1" to help center the wheels on low trucks.
I know this means, moving sway bar mounts, idler arm holes, and the steering box holes,... but to me it would be worth it.
Especially if you could weld and do it yourself,... which I know you can.

I remember seeing this mod years ago on a squarebody blazer converted to 2wd.
But I can't remember which magazine it was in.

[gringoloco]

Originally Posted by knomadd

Dang, a few days away and I've missed a lot of conversation. Your plan sounds great! I'll be following along.

Welcome aboard!

Originally Posted by lolife99

Funny you mention that.
I've always thought about these conversions in great depth.
For me personally,... I would move the entire crossmember forward 1" to help center the wheels on low trucks.
I know this means, moving sway bar mounts, idler arm holes, and the steering box holes,... but to me it would be worth it.
Especially if you could weld and do it yourself,... which I know you can.

I remember seeing this mod years ago on a squarebody blazer converted to 2wd.
But I can't remember which magazine it was in.

I think you could get away with moving the whole crossmember forward a bit, without interfering with the steering center link. Possibly combine that with the lower control arm “caster mod” for more centering. We will see how it pans out, but I will play with it a bit to see what works best.

If you think about it, moving the whole crossmember forward isn’t a whole lot different from using 1” forward tubular arms, as far as steering linkage geometry is concerned when related to the pitman and idler arm locations (someone please correct me if I’m under-thinking this). Stock type anti-sway bars can have the ends trimmed and linkage style bars might be able to absorb the difference (or have bushing locations redrilled, as you stated, thankfully, I’m starting from scratch there).

All that to say, it may not be too terribly complicated to gain that extra inch. 104” wheelbase is stock, so probably somewhere in the neighborhood of 105” will look “right”. I’m pretty excited to finally get to play with one (the yellow Blazer was already converted when I bought it). Let’s find out together

[smbrouss70]

Originally Posted by gringoloco

Yes, everyone that my wife has mentioned this to at her work thinks I’m a lunatic and won’t talk to me anymore... I’ll just go over here and be crazy by myself

Trust me, you won't be lonely in the crazy corner!

Originally Posted by gringoloco

Welcome aboard!

I think you could get away with moving the whole crossmember forward a bit, without interfering with the steering center link. Possibly combine that with the lower control arm “caster mod” for more centering. We will see how it pans out, but I will play with it a bit to see what works best.

If you think about it, moving the whole crossmember forward isn’t a whole lot different from using 1” forward tubular arms, as far as steering linkage geometry is concerned when related to the pitman and idler arm locations (someone please correct me if I’m under-thinking this). Stock type anti-sway bars can have the ends trimmed and linkage style bars might be able to absorb the difference (or have bushing locations redrilled, as you stated, thankfully, I’m starting from scratch there).

All that to say, it may not be too terribly complicated to gain that extra inch. 104” wheelbase is stock, so probably somewhere in the neighborhood of 105” will look “right”. I’m pretty excited to finally get to play with one (the yellow Blazer was already converted when I bought it). Let’s find out together

You might have the inner tie-rod ends get too close to the crossmember if you move it forward, but that should be able to be "clearanced" or notched to provide enough room for them. Another issue that would come into play only if you are bagging it, is the fact that the steering column shaft may interfere with the upper control arm when laid out. Again, an easy fix for someone with your particular skill set.

[gringoloco]

Originally Posted by smbrouss70

Trust me, you won't be lonely in the crazy corner!

This is why I like you guys, you get my brand of crazy

Originally Posted by smbrouss70

You might have the inner tie-rod ends get too close to the crossmember if you move it forward, but that should be able to be "clearanced" or notched to provide enough room for them. Another issue that would come into play only if you are bagging it, is the fact that the steering column shaft may interfere with the upper control arm when laid out. Again, an easy fix for someone with your particular skill set.

It’s a delicate balance between keeping it easy and hacking it up. I’d like to keep it bolt-in-ish. At least that’s the plan, for now...

[smbrouss70]

BTW, this explanation from Livrat sounds like the easiest way to correctly locate the holes for a 4x4 to 2wd swap. I don't know if you have access to a set of front framerails off of a 2wd truck though.

Originally Posted by Livrat

The swap is a fairly easy one to do... I have done 6 of them in the last 20 years.. Mainly because I like 2WD blazers plus they are rare and are worth way more than 4X4's.. (at least here in WA)
The simplest way is to aquire a 71/72 2WD donor truck.. You will need the entire front crossmember assembly... all the brake lines... steering box.. motor mount towers.. shift linkage...(BB and SB are different)... radiator core support brackets... transmission crossmember.. and ... make sure to keep all the nuts and bolts.
Remove everything you can unbolt from the frame on the 4X4.. Get yourself a big hammer and chisel.. and knock the rivets out of the front spring hangers/core support brackets.. same with the rear spring hangars and outer shock plates... and remove..
I have found if you cut the donor trucks frame rails off at the firewall.. cut them into three pieces lengthwise at the corners, You can litterally bolt them on top of the frame on the conversion truck to line up the holes that need to be drilled... use a transfer punch to mark them... (available at most tool stores) then start drilling.. be prepared for alot of sweating..... then you should be able to bolt the 2WD front suspension crossmember and steering componets in and have the truck back on the ground... Bolt on the front radiator core brackets.. and all brake lines... slide the 2WD trans crossmember between frame rails close to where it should go... Whew.. by this time the hardest part is over... and you should have a steering and stopping truck...
For the engine mount towers I prefer to use the 72 style ones because they are stronger than the 67-71 ones.... since they are fairly expensive and you are at this point into drilling holes.. I opt to get them out of the 73-80 trucks.. BUT there are more than one style and you need to get the correct ones.. One will make your engine sit up too high... I can draw a picture of the style you need if you decide to go for it... (not sure exactly which truck/engine combo I get them from.. I just know what ones to look for..)
Depending on which engine/trans combo you will use you may or may not have to drill the holes for the engine towers.. I prefer to use a bare block and transmission assy and "mock it up' into the truck.. the lower bolts on the engine tower will usually just "line up"... again transfer punch the holes and drill then bolt them in.. On the transmission crossmember I like to use a 10inch long drill bit to drill both top and bottom holes at once... then bolt all together... On the trans shift linkage again.. you may or may not have to drill holes for the frame bracket.. will have to mock it up to see..
On to the rear end...
if the 4X4 is not a 69 ...(69 rear ends are narrower than the rest)
I opt to just put the 4X4 rear end on top of the leaf springs with either a flip kit.. or by welding on new spring perches.. I use "Moroso" spring perches for a Dana 60 which have the same tube diameter... If you are not a welder and are not familiar with setting the "pinion angle".. a flip kit would be the preferred method.... Then I use the axles and brake drums off the a 2WD to get the 5 lug pattern... Its a straight swap... You can use Axles/brakes from any 2WD 1971-80 12 bolt...
IF you decide to go ahead... feel free to email me and ask any questions... I love to talk trucks.. Just dont like working on em anymore...

[gringoloco]

Originally Posted by smbrouss70

BTW, this explanation from Livrat sounds like the easiest way to correctly locate the holes for a 4x4 to 2wd swap. I don't know if you have access to a set of front framerails off of a 2wd truck though.

I do like this method, though it seems like you’d use a lot of cutoff wheels if you’re a regular guy like me without a plasma cutter. It think it would be easier to build a paper template or rubbing transfer. I at least have access to a torn-down C10, though there is a dropmember in the way now. Wish I’d had the foresight to build a template while it was apart Regardless, I may not end up in exactly the stock position, but we’ll see!

[gringoloco]

These frame diagrams have been reposted a number of times here on the forum. They do not contain all of the required info, but are a great start. Big thanks to the original poster, Rod, whoever/wherever you are...

[gringoloco]

Notice that the front crossmember on the 2wd is located based on axle centerline (CL), which is only possible to find with control arms and spindles installed, and at ride height. It is much easier to locate axle CL on the 4wd frame as it’s centered in the bumpstops.

We can decipher that the factory placed the front axle CL 21.90” behind the core support bushing CL. This is found by subtracting the 16.50” measurement from the seemingly arbitrary line drawn 38.40” behind the core support mounts. This measurement is the same on both 4wd and 2wd frames.

[lolife99]

Originally Posted by gringoloco

Notice that the front crossmember on the 2wd is located based on axle centerline (CL), which is only possible to find with control arms and spindles installed, and at ride height. It is much easier to locate axle CL on the 4wd frame as it’s centered in the bumpstops.

We can decipher that the factory placed the front axle CL 21.90” behind the core support bushing CL. This is found by subtracting the 16.50” measurement from the seemingly arbitrary line drawn 38.40” behind the core support mounts. This measurement is the same on both 4wd and 2wd frames.

Any chance you can "plumb bob" the centerline of the front wheels by using the blazers front sheeetmetal with all the suspension removed.
Kinda like the guys did in the old days when addinging subframes to straight axle vehicles.
Draw everything out on the floor.
I agree you will have to assemble some of the crossmember,... but without springs in place it shouldn't be too hard to mock up exactly where you want the wheel to set in the front fenders.
Or am I over simplifying things?

[gringoloco]

Originally Posted by lolife99

Any chance you can "plumb bob" the centerline of the front wheels by using the blazers front sheeetmetal with all the suspension removed.
Kinda like the guys did in the old days when addinging subframes to straight axle vehicles.
Draw everything out on the floor.
I agree you will have to assemble some of the crossmember,... but without springs in place it shouldn't be too hard to mock up exactly where you want the wheel to set in the front fenders.
Or am I over simplifying things?

That’s almost exactly what I have in mind. I want to get all of the DEG parts bolted in place, hang the rear suspension, and plot the front from there. I plan to temporarily hang the front suspension and steering to see what works best for visual and functional placement, then drill and bolt for final install.

[gringoloco]

Moving to the rear, we see that GM located the trailing arm crossmember 70.43” from the core support CL. This is derived by adding the seemingly arbitrary 38.40” reference from the core support bushing CL to the 32.03” measurement, which appears to align with the forward-most upper crossmember mounting hole. Correctly ocating the trailing arm crossmember also correctly located the rear axle CL.

This measurement seems to fairly accurately correlate with findings here on the board of previous conversions (including my own), which utilize existing holes in the 4wd frame, following removal of the existing bracket (photo courtesy member notsolo). This reference gets us in the neighborhood. We will see how it pans-out with the location of the DEG c-notch, which due to the contours of the frame, is relatively fixed.

[gringoloco]

Here’s a pic of my old Blazer showing how the wheel is centered in the rear wheel well when using the “existing hole” method:

[gringoloco]

Member sierragrande71 located his front crossmember using two existing holes in the frame, which looks to fairly closely center the front wheels in the arches. Kinda hard to tell, due to the angle and height of fenders.