Polar Bear Suburban

[DirtyLarry]

Originally Posted by jbclassix

Did you ever get the oily brakes ok K10 dilemma sorted out? If you did I missed it
Posted via Mobile Device

It seems to be cured. I basically replaced every single bearing, race and seal in the damn thing. Last month we went on our annual Desert Trip and turned 1,100 miles on it with no issue. So far so good

[ScottsdaleK5]

Hey Larry, I just finished reading through this thread and your attention to detail is immaculate..! I wish I had the patience to do the same; I'm always too eager to get it in and get it going! However, someday when things slow down I'd like to do the same.. The 'Burb looks great and you got a great deal on it! I'm quite jealous!

On to my questions, I have an '89 K5 Blazer that I plan on doing an NV4500 swap on.. It came stock with a 700r4 but after three of those I replaced it with a th350 adapted to my NP241. Now from what I understand it needs a 32 spline input shaft to work with a NV4500. I was wondering if your case already had the 32 splice shaft or if you put one in.. Is it best to find a case that has the 32 spline shaft or just buy a new one?

Thanks for the help! My Blazer will probably end up with an LQ4 for now but would really love to have an 8.1L in it.. they're just so damned expensive!

[DirtyLarry]

Originally Posted by ScottsdaleK5

Hey Larry, I just finished reading through this thread and your attention to detail is immaculate..! I wish I had the patience to do the same; I'm always too eager to get it in and get it going! However, someday when things slow down I'd like to do the same.. The 'Burb looks great and you got a great deal on it! I'm quite jealous!

On to my questions, I have an '89 K5 Blazer that I plan on doing an NV4500 swap on.. It came stock with a 700r4 but after three of those I replaced it with a th350 adapted to my NP241. Now from what I understand it needs a 32 spline input shaft to work with a NV4500. I was wondering if your case already had the 32 splice shaft or if you put one in.. Is it best to find a case that has the 32 spline shaft or just buy a new one?

Thanks for the help! My Blazer will probably end up with an LQ4 for now but would really love to have an 8.1L in it.. they're just so damned expensive!

Welcome to the forums and thanks for the compliments!

Correct, you will need a 32 spline 241 or 208. 32 spline cased came behind TH400 and SM465 manual transmissions. My Burb was originally a SM465 so it already had a 32 spline 241 in it. Swapping a 32 spline input into a 241 is easy enough but finding the input will be the hard part. Might was well keep your eyes peeled for a complete 32 spline tcase and just use it.

LQ4’s are great engines but once you really start digging into researching the Gen III “LS” small block engine swaps and 8.1L swaps you’ll find there isn’t that much difference in cost. The 8.1L does not require exotic engine mounts, aftermarket accessory brackets to run A/C and the scavenger hunt Gen III swappers go on to find an inexpensive exhaust manifold that doesn’t require hacking up the frame. Mating a Gen III to a manual trans can also be another bag of worms. With the 8.1L, they bolt right in just as any old BBC or SBC and any older BBC header/manifold will fit the engine. It does require a unique flywheel but the clutch used is the typical 12" clutch GM used for eons. I see 8.1L’s pop up often for $1000 whereas Gen III’s are pulling bigger money because of their popularity. When people say LS engines are cheaper to swap I have to chuckle.

Good luck with your project!

[83GMCK2500]

Originally Posted by DirtyLarry

Welcome to the forums and thanks for the compliments!

Correct, you will need a 32 spline 241 or 208. 32 spline cased came behind TH400 and SM465 manual transmissions. My Burb was originally a SM465 so it already had a 32 spline 241 in it. Swapping a 32 spline input into a 241 is easy enough but finding the input will be the hard part. Might was well keep your eyes peeled for a complete 32 spline tcase and just use it.

LQ4’s are great engines but once you really start digging into researching the Gen III “LS” small block engine swaps and 8.1L swaps you’ll find there isn’t that much difference in cost. The 8.1L does not require exotic engine mounts, aftermarket accessory brackets to run A/C and the scavenger hunt Gen III swappers go on to find an inexpensive exhaust manifold that doesn’t require hacking up the frame. Mating a Gen III to a manual trans can also be another bag of worms. With the 8.1L, they bolt right in just as any old BBC or SBC and any older BBC header/manifold will fit the engine. It does require a unique flywheel but the clutch used is the typical 12" clutch GM used for eons. I see 8.1L’s pop up often for $1000 whereas Gen III’s are pulling bigger money because of their popularity. When people say LS engines are cheaper to swap I have to chuckle.

Good luck with your project!

Not quite hen's teeth but 32 spline is also behind the 4L80-E in '91 V-series, also nets you the electric VSS.

[DirtyLarry]

Originally Posted by 83GMCK2500

Not quite hen's teeth but 32 spline is also behind the 4L80-E in '91 V-series, also nets you the electric VSS.

Yeah, that is for sure albeit 91’s are hard to find. For that matter a 1985 and newer NP205 also have the round pattern that fits the NV4500 and 32 splines as well. I don’t find 1990/1991 donor tcases with VSS as a bonus for those of us running older trucks with speedo cables and manual transmissions. VSS isn’t required for the NV4500 nor required for Gen III/8.1L swaps. VSS on an 1989 and older square body (cable driven speedo) is nothing but a hindrance that forces many sheeple into buy expensive Dakota Digital type clusters when there really is no need to. Neither of my 8.1L/NV4500 rigs run VSS or anything aftermarket in the clusters. The cluster doesn’t know if there is a late model SFI big block under the hood or a timid little TBI 5.7L and the engines have no idea (or care) how fast the truck is going. For those reasons, I’ve personally steered clear of 90/91 square body tcases. If I was running a 4L80E that might be a different story where VSS is more important.

[ScottsdaleK5]

Originally Posted by DirtyLarry

Yeah, that is for sure albeit 91’s are hard to find. For that matter a 1985 and newer NP205 also have the round pattern that fits the NV4500 and 32 splines as well. I don’t find 1990/1991 donor tcases with VSS as a bonus for those of us running older trucks with speedo cables and manual transmissions. VSS isn’t required for the NV4500 nor required for Gen III/8.1L swaps. VSS on an 1989 and older square body (cable driven speedo) is nothing but a hindrance that forces many sheeple into buy expensive Dakota Digital type clusters when there really is no need to. Neither of my 8.1L/NV4500 rigs run VSS or anything aftermarket in the clusters. The cluster doesn’t know if there is a late model SFI big block under the hood or a timid little TBI 5.7L and the engines have no idea (or care) how fast the truck is going. For those reasons, I’ve personally steered clear of 90/91 square body tcases. If I was running a 4L80E that might be a different story where VSS is more important.

I will keep my eyes open for a 32 spline shaft, thanks for the help! I am pretty partial to my np241 for how little I use it. It doesn't get a lot of strenuous use so I don't need the toughest tcase out there and its not extremely heavy like that of a cast iron case..

I appreciate your help! I will stop hijacking your thread now! I am sure in the future I will be asking more questions about the swap!

[Jonboy]

I ended up with a 32 spline NP241 and that's how my Jimmy project spiraled out of control. I originally was going to just flip the truck with a fresher 350 and a rebuilt TH350/NP203, but a low mile parts truck we acquired (90 3/4 ton Suburban ambulance) gave up it's transfer case and axles. A 4L80e bolts right to the case, and you might as well do an LS in front of that, so that's where I am at now. I am wanting to mimic your suspension lift for my Jimmy too.

[ERASER5]

So you are down sizing the cam? Was it a drive-ability problem or tuning issues?

[DirtyLarry]

Originally Posted by ERASER5

So you are down sizing the cam? Was it a drive-ability problem or tuning issues?

Yep, the RayLar cam came out last night. Both actually, but tuning is the main issue causing less than sterling drivability habits. I give up on dealing with anymore local tuners. The rig ran like a rapped ape at WOT but the overall drivability was sucktastic. Major idle flare during shifting, hunting idle, etc. I almost decided to drive it to San Diego for a business trip back in October and have RayLar’s tuner fix it up but he was pretty certain to clean it up I would need to convert to an electronic throttle and add VSS. An automatic trans would also make the tuning easier according to several of the tuner guys. I didn’t feel like doing any of that and a brand new stock GM 8.1L cam was only $140 from work and I had the tune from the K10 copied in burnt into the Burb. The K10 runs great even in stock form so in theory, the Burb should run exactly like the K10 as they will be identical aside from the burb having headers and the K10 running manifolds.

Rob and I got the engine out yesterday and swapped the cam last night. Just need to pick up some gaskets tomorrow and get engine dropped in tomorrow night. Hope to have it all wrapped up by the time the girls get home from visiting our in-laws in Florida Thursday.

At the end of the day, I think the RayLar 202 cam would be the cats meow for something with an auto trans and electronic throttle. The benefit of the electronic throttle would be to for the tuner to play with the throttle cracker to help with idling instead of running the IAC so aggressively. I don’t like electronic throttles in 4x4’s because they’re too touchy off-road. I will miss the big power the Raylar cam gave it though. It was fun beating down unsuspecting diesel heybro dudes for a while.

[DirtyLarry]

Christmas vacation wrench-a-thon! Rob on his K5 and me on the Burb


Rob getting after the rear window gremlins

[1985-GMC]

I'm glad you're getting that sorted out.

Have you put any thought into a roof rack for the burb?

[DirtyLarry]

Originally Posted by 1985-GMC

I'm glad you're getting that sorted out.

Have you put any thought into a roof rack for the burb?

Me too! Hope this gets it sorted out once and for all.

No, no plans on doing anything on the roof of the Burb. The K10 does all the long distance trips so no real need to add roof storage on the burb as it doesn’t go out as far or for as long. Rob has a roof basket for his K5 though.

[1985-GMC]

That's what I figured. My burb is going to be my road trip/ trail rig so I'm trying to figure out a roof rack but I don't want anything bolted to the roof or drip rails.

[DirtyLarry]

Well, well, well! I was finally was able to take it on a test drive this morning and I am a completely satisfied camper! It runs identical to the K10 as I had hoped! Tons of power with Cadillac drivablity manors. No more idle flares, hunting idle, dying, jerky jerk operation…. blah, blah blah…. Ah, and having the low-end grunt to let it lug itself around is so nice. Best of both worlds. Sucks it took 6 months to get here but it was worth it in the end.

You’re all probably tired of pictures but these are the latest pictures with the final hose/harness routing and clipping. It is now DONE under the hood with respect to the 8.1L swap. Speaking of the hood, that is the last thing that needs attention….the hood needs adjusted badly! I’ll try to get some videos soon.

Engine out for the cam swap, day after Christmas


Made stand off brackets for the hydroboost hose from the pump to the booster. This is a GMT400 booster hose (those hose with the blue clamp).


Made another stand off bracket for the hose going to the pump. It has a p-clip holding to the stud to prevent the metal portion of the hose from vibrating resulting in fatigue cracks










Might have a leak at the p/s pump that I need to keep my eye on. It didn’t leak over night after I wiped it off


Final Final!



This should be the end of the engine swap reporting for a while. Next up I need to adjust the hood, driver’s door and get after the horrible driveline angles causing major highway vibrations. Aiming to take it on a long roadtrip in May to the Overland Expo

[jbclassix]

I see green drops, is that what you're talking about?

[DirtyLarry]

Originally Posted by jbclassix

I see green drops, is that what you're talking about?

Haha, the green antifreeze is overspill from topping off the radiator and burping the stubborn sumbish

....that is what I am talking about!

[jbclassix]

got a beast there for sure. I would love to have a 2001+ 8.1L burb, but since it would have to be a daily driver, I'll have to settle for the measly 6.5L.

[Dieselwrencher]

Larry, glad to hear you got it figured out and running great. I'm sure that was a huge pita dealing with.

[Duramax40]

Very nice work I like the attention to detail. I had a question on the underwood factory wiring. I have an 89 big block truck that I converted to an lq9 and I'm starting to dissect the TBI harness out. My LS harnes is already done. What wires did you end up keeping. So far Iv found the 12v and couple sensor wires but everything else is confusing with out a year specific schematic book. It doesn't look like you had to keep that many to make it work. Great build!!! Thanks for any in site

[DirtyLarry]

Originally Posted by Duramax40

Very nice work I like the attention to detail. I had a question on the underwood factory wiring. I have an 89 big block truck that I converted to an lq9 and I'm starting to dissect the TBI harness out. My LS harnes is already done. What wires did you end up keeping. So far Iv found the 12v and couple sensor wires but everything else is confusing with out a year specific schematic book. It doesn't look like you had to keep that many to make it work. Great build!!! Thanks for any in site

Thank you sir!

The best thing you can do is to go on Ebay and buy a factory GM wiring diagram manual…. Like this one that is only $10. (I’m assuming your 89 is a square body not a GMT400)

Without a good roadmap you will have a much more difficult time knowing exactly what to cut away. As far as my Suburban, it was very straight forward. All I kept was a 12v hot, 12v key on, starting and charging circuits and gauges (oil, volt & temp). On that other hand, I just did the same thing to a 91 K5 for a 5.3L swap but it was much more complicated compared to my Suburban as it has an auto trans and electric speedo plus it had many ABS wires to be pruned away.

Get a GM Wiring Diagram Manual…..don’t even bother with Chiltons, Hayes, All-Data or any aftermarket diagram. Get the real deal!

Don't let pictures like this one scare you too bad

[Billhilly]

Hey Larry,
Just had a quick question about Duratrac's. I have just finished a drawn out build on my K2500 (http://67-72chevytrucks.com/vboard/s...d.php?t=217490) and am running 285 75 16 Duratracs on it. I imported these tyres and they are only now becoming available down here so there is no real 'local knowledge' as such. I don't know anyone running these tyres, I am wondering what sort of pressure you are running in yours? I figure Polar Bear would be a similar weight to my (empty) truck. I am currently trying 55lbs. I've only done 1500 miles so far and have gone from 50lb to 55lb. Still undecided and looking for opinions!
Loving your 8.1 swaps, I think one would be fun in my truck! Oh, and a five speed swap!

[DirtyLarry]

Originally Posted by Billhilly

Hey Larry,
Just had a quick question about Duratrac's. I have just finished a drawn out build on my K2500 (http://67-72chevytrucks.com/vboard/s...d.php?t=217490) and am running 285 75 16 Duratracs on it. I imported these tyres and they are only now becoming available down here so there is no real 'local knowledge' as such. I don't know anyone running these tyres, I am wondering what sort of pressure you are running in yours? I figure Polar Bear would be a similar weight to my (empty) truck. I am currently trying 55lbs. I've only done 1500 miles so far and have gone from 50lb to 55lb. Still undecided and looking for opinions!
Loving your 8.1 swaps, I think one would be fun in my truck! Oh, and a five speed swap!

Hey Billhilly!

Yeah, I’ve been watching your build but mostly through my phone, which isn’t easy to make comments with. Also dug your pictures on the mountain. Too cool!

I tell ya, I really like these Duratracs! The set on the Polar Bear really belong on the K10 but the bear borrowed them for a while to chase a vibration issue (turned out the vibration wasn’t the tires anyway). I need to swap them back soon. Anyway, I run the air pressure at 50 psi front/rear when they are on the Burb and 50 psi front/55 psi rear when they are on the K10 due to the weight of the camper. They seem to be wearing very well. In fact, they don’t show any wear hardly at all although I only have about 7,000 to 8,000 miles on them. Maybe a little more…. I kind of lost track of the miles being I’ve swapped them back and forth from truck to burb a few times. I highly recommend them. You going to love them! I have a set of 285 Duratracs on my Silverado HD as well but those probably only have a couple thousand miles on them if that.

Thanks for the engine swap comments. They've definitely been fun to do!

[Billhilly]

Originally Posted by DirtyLarry

Hey Billhilly!

Yeah, I’ve been watching your build but mostly through my phone, which isn’t easy to make comments with. Also dug your pictures on the mountain. Too cool!

Thanks! It's hardly 1000 miles off road in UT, but I'm trying. Given the scale of things down here, well, it's limiting!

I tell ya, I really like these Duratracs! The set on the Polar Bear really belong on the K10 but the bear borrowed them for a while to chase a vibration issue (turned out the vibration wasn’t the tires anyway). I need to swap them back soon. Anyway, I run the air pressure at 50 psi front/rear when they are on the Burb and 50 psi front/55 psi rear when they are on the K10 due to the weight of the camper. They seem to be wearing very well. In fact, they don’t show any wear hardly at all although I only have about 7,000 to 8,000 miles on them. Maybe a little more…. I kind of lost track of the miles being I’ve swapped them back and forth from truck to burb a few times. I highly recommend them. You going to love them! I have a set of 285 Duratracs on my Silverado HD as well but those probably only have a couple thousand miles on them if that.

I thought they were on your K10, but trolling through your threads looking for pic's, the first photo I found was one of the Burb with them on. Good to hear you are getting a great run out of them. And I'm obviously pretty close with pressures too.

Thanks for the engine swap comments. They've definitely been fun to do!

I'm wondering what freight is for a LQ9/4500/205 combo, CO to NZ........?!

Oh, this is the photo I found on your thread. She must love the trucks, and the camper must be perfect for her!

[NastyBuzzard]

Originally Posted by DirtyLarry

Yep....Exactly, it will do for now.

The Polar Bear will eventually get the same 14FF infusion as the last Suburban of this era that came through the Big Block Garage. Lift too.

This Sub was a bit rough on the outside but had a fresh marine turbo 6.5L when it left. This one lives in Detroit, MI now where it got fresh paint and other upgrades.




Junk 14 bolt 9.5” semi-floater ready to be returned to the salvage yard for core cost after it was pruned from the black Sub

I hate to bring up old stuff but do you have a thread or any info on this? I want to put a 6.5L Turbo Diesel in my 88 Crew Cab as well as a NV4500 after I finish converting to 4wd.

[DirtyLarry]

Nah, I sure don't. That project was 10 years ago in 2006. Built it for a friend that lives in Detroit. It got an AM General 6.5L backed by a TH400. He swapped in a 4L80E and painted it when it got to Michigan.