The Camp 4x4 Bus - 1973 Suburban 8.1 Swap & Build

FBJR

Adventurer
Cool video, is that the new place? Router, lots of lights and still cleaner than my garage.

So is that the spectre air cleaner? Been looking to do similar on mine but still want AC.
 

camp4x4

Adventurer
Cool video, is that the new place? Router, lots of lights and still cleaner than my garage.

So is that the spectre air cleaner? Been looking to do similar on mine but still want AC.
Yep, new place. Have done a decent amount of tidying up, but there's a fair bit more to do... eventually...

And yeah, that's the Spectre air box. kind of big, but not excessively so. The Vintage Air kit is on its way, so I'm going to wait for that before I go cutting holes so I can see exactly what I'd need to modify on that block off plate.
 

FBJR

Adventurer
The vintage air would probably save me room over there, will have to see. They cut the AC system up for the turbo on the 6.2, but I'm going cummings later. I will say the 6.2 power surprised me a little.
 

Oilbrnr

Active member
Yeah. That was my truck. Grew up in that thing! Learned how to drive in her around 10 years old. Towed our Airsteam to Mazatlan. Twice. Countless trips to Lake Powell. Endless hours exploring AZ and UT.

GET’r DONE or I might repo her! 😀

I’m coming over this weekend to pick up a FWC in Novato Aaron. Not sure how far away you are, but it be fun to see the old girl. PM me.

-don-
 

camp4x4

Adventurer
Any updates? I check in every few months and haven't seen anything in a while.
No updates lately. I did get a 2-post lift installed in the garage, and I've been working on getting the garage better organized (moving to a new house doesn't seem to really be done for quite a while...). I've got a 24 Hours of LeMons race car project that's been taking my focus lately, but that's nearly done so I'm hoping to take the project momentum from that and put it into getting this finished.

Yeah. That was my truck. Grew up in that thing! Learned how to drive in her around 10 years old. Towed our Airsteam to Mazatlan. Twice. Countless trips to Lake Powell. Endless hours exploring AZ and UT.

GET’r DONE or I might repo her! 😀

I’m coming over this weekend to pick up a FWC in Novato Aaron. Not sure how far away you are, but it be fun to see the old girl. PM me.

-don-
PM sent! Hope you can make it out. Novato is about 2 1/2 hrs away so that might not be realistic... if you got a day and wanna help me start wrenching on it... ;)
 

Skinny

Active member
So I have an 80% identical truck. I started with some $99 Jegs long tube specials and I was good on frame clearance but they occupy the same space as the shackles. At some point I need to either rework what I have or maybe go to the ones you are running. Still not sure what is easiest. I need to do the whole thing as I fabbed up a true dual 2" system when I had a 6.2 in it. Thinking maybe a dual 3"?

Quick rundown...

8.1 4l80 205

All CUCV running gear from an ambulance

Airbox fabbed using battery box, largest canister filter that would fit sits in there so the snorkel is actually functional

I just did a webasto gas heater and changed the trucks rear hear so there is more room on the floor

Still need to do a roof rack with a solar panel

Left side of bumper will have a DC Generator (this is the kit that I sell www.affordabledcgenerators.com) with an auto start controller

This is what the Dante's Peak Suburban would look like of it mated to a CUCV. Of course my other ride is a matching M1031 generator truck.


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zoomad75

Observer
So I have an 80% identical truck. I started with some $99 Jegs long tube specials and I was good on frame clearance but they occupy the same space as the shackles. At some point I need to either rework what I have or maybe go to the ones you are running. Still not sure what is easiest. I need to do the whole thing as I fabbed up a true dual 2" system when I had a 6.2 in it. Thinking maybe a dual 3"?

Quick rundown...

8.1 4l80 205

All CUCV running gear from an ambulance

Airbox fabbed using battery box, largest canister filter that would fit sits in there so the snorkel is actually functional

I just did a webasto gas heater and changed the trucks rear hear so there is more room on the floor

Still need to do a roof rack with a solar panel

Left side of bumper will have a DC Generator (this is the kit that I sell www.affordabledcgenerators.com) with an auto start controller

This is what the Dante's Peak Suburban would look like of it mated to a CUCV. Of course my other ride is a matching M1031 generator truck.


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Nice Burb! I like the air box setup too. As far as the exhaust goes, I'm running stock big block truck manifolds to avoid the exact interference you have. I had a full 2.5" true dual setup with x-pipe from there. Zero clearance issues at the shackles. Given the fact that these trucks don't go to the track, we aren't leaving much on the table for power. My Blazer was tipping the scales at 6500 pounds prior to the big block install so it's gained a few pounds. It flat hauls the mail as it is. Having the extra HP on the top end that you rarely use is not worth some of the issues with the interference at the shackle. Plus as you noted the exhaust necks down to 2" after the collector so what gain you had with the headers is dropping off with the smaller exhaust pipes.

The other option is shorty headers. That is if you want to reconfigure the exhaust for it. I think a true dual 2.5" setup or 2.5" dual into single 3" would be ideal to support the 8.1 without the need for full-length headers. Look up Larry's Polar Bear Burb as it's a very good example of how to package the 2.5" pipes with an x-pipe under a burb.
 

Skinny

Active member
When you say stock big block manifolds square body 454 or late model 8.1?

I may just go shorty headers. I'm fine with reworking the while exhaust. I can reuse a lot of it on my CUCV that still has the 6.2 diesel. I just want to eliminate frame and shackle interference before going further.

I'm thinking a true dual 3". Whether or not it needs a crossover...haven't given that any thought yet. I have plenty of room under this truck so packaging isnt a huge problem.

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zoomad75

Observer
When you say stock big block manifolds square body 454 or late model 8.1?

I may just go shorty headers. I'm fine with reworking the while exhaust. I can reuse a lot of it on my CUCV that still has the 6.2 diesel. I just want to eliminate frame and shackle interference before going further.

I'm thinking a true dual 3". Whether or not it needs a crossover...haven't given that any thought yet. I have plenty of room under this truck so packaging isnt a huge problem.

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8.1 manifolds won't fit between the squarebody frame rails without cutting the rails. Mine are late squarebody cast manifolds. They tuck in tight to the block. but TBI manifolds from GMT400 trucks fit too.
Here's a shot of mine with less in the way to block the view.


Larry used Sanderson shorty headers for a Chevelle and they cleared everything well. Not cheap, but the fit is worth the price, thick flanges too.

The use of a crossover is purely out of preference. The 8.1 shares the same firing order as the LS engines. 8.1's without a crossover sound different than a standard small block or big block with the classic firing order. It's more raspy. Some may not notice, but the crossover tones that down.

The idea for true duals in 3" pipes is good until you try to package it. I had a hard time running the passenger side pipe past the frame and t-case with 2.25" pipe when I ran the 5.3 in mine. So when we scrapped the 2.25" system when the 8.1 came in we went with 2.5" and changed the routing. The passenger side pipe crossed under and behind the engine to the driver side. That cleared the t-case better with the x-pipe and split back out to separate mufflers and dump out behind the rear wheels. The 2.5" is tight still going past the fuel tank on either side. I think the 2.5" pipe is a good compremise and still can be packaged under the truck.
 

Skinny

Active member
I thought about this for a few days. I may try to rework the end of the header to clear the shackle. I have the rasp you talk about and I like it. It scares small children :)

I think the only fitment issue is getting a 3" pipe around the tcase. I have a 205 so it is big. I'd really have to stick my head in there to see.



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zoomad75

Observer
I thought about this for a few days. I may try to rework the end of the header to clear the shackle. I have the rasp you talk about and I like it. It scares small children :)

I think the only fitment issue is getting a 3" pipe around the tcase. I have a 205 so it is big. I'd really have to stick my head in there to see.



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3" is going to be hard to route between the 205 and the frame. With 2.5" I was really tight to the point I was concerned about cooking the fuel lines. I'm not sure 3" will fit.
 

Skinny

Active member
Yeah I know that feeling.

What about an oval? Maybe a squeeze would help without sacrificing too much.

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