LS3, 4l80e, Np205 in 1972 Blazer
 

I was kind of hogging another thread and figured I would make a new one. I am swapping an LS3 with a 4l80e and NP205 Tcase into my k5. This has been done and I've read a lot about it, but I haven't seen a lot of info on here specific to the blazer. One person did it using the Lomax np205, but at $2,700 assembled and the fact I don't really offroad I wanted to do it a little cheaper using my stock t-case. I picked up a 4l80e from my tranny guy and had him swap out the rear shaft for a fully splined setup. It has 6 1/4" shaft from the back of the case. I called Offroad Designs and picked up the adapter and input kit for the t-case. Since I had the full spline I was able to use the short input which is cheaper. It was right around $480 shipped for everything. They said the rear shaft can be cut to 4 1/2" and it will bolt right up. Using the 2wd 4L80e also gives me the VSS output which some 4wd transmissions didn't have. This can be worked around but I figured I would make it as easy as possible.

Plans are to get it mocked up in the next few weeks and put the T-case in the stock location. I also have a dirty dingo front engine cross-member for the ls3. Anyone else with info and suggestions is appreciated and this is a first for me so feel free to correct any statements that may be incorrect.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

So I decided to get a rebuilt 205 from Offroad Design rather than find a machine shop. Everyone I called local just didn't know what I was talking about. So for 1150 shipped to my house I get a rebuilt unit with the 32 spline input installed. I'll probably sell my 205 to offset the cost.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

I have a beeeeeefy Np242AMG if you want/need something of that level. I'm not gonna have any use for it, and its only got like 10k miles on it.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

Thanks br3w and that's an Interesting offer, but I already ordered and paid for the 205. I've only heard of that case so I don't know much about it and have limited knowledge of the swaps. This is my first ls swap as well so it's a learning experience all around.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

Brew is that from a hummer? Left side drop?...I'm thinking he's using np205 right side drop..if it came from a hummer I bet it is a beast...would be great in a all wheel drive hotrod..

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

I believe it is for a hummer and pretty heavy duty. Probably not something I would need as mine is more of a driver and for fun.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

Its a Mil-spec xfer for stuff based on the Hummer chassis. Its still in its airdrop resupply shell (and its really freaking cool). Somethigsomethingsomething Surplus Auction lol.

I don't know dick about 4wd stuff, I just know how to end up with weird stuff.
Its rated to 1200lb/ft.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

Does anyone know if I need to plug the two oil holes in the back of the case so no fluid gets swapped?

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

Which holes? Can you take a pic? That would help answer the question.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

The top and bottom.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

Nope. Don't know the answer to that one. There are some guys on here that know everything about the 4L80E. Maybe one of them will chime in.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

Very happy with mine.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

I'm happy to hear yours is working out. I have heard good things about ORD that's why I went with them.

After doing research there are people saying there is no need to plug them.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

I was reading that you DID need to plug the hole. The larger hole that looks like a freeze plug carries oil to the extension housing and the bushing within on 2wd trucks.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

I was talking about the two smaller holes at 12 and 6. From what I read it's not necessary. The other hole at 3 is already plugged with a plastic plug and does need to have it. A bit weird it's there considering it was a 2wd trans.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

Here's some more talk on it.

http://www.pirate4x4.com/forum/chevy...topics/1062002

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

Well I went riding quads Saturday and had a pretty nasty wreck. I have two broken ribs, a broken collarbone, fractured wrist and concussion. I'm feeling better today but have around 6 weeks of recovery.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

Ooouucccchhhhh!!!

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

Wow! Been there done that with dirt bikes. Get well soon. Best of luck.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

Thanks guys. I'm feeling a lot better and really the only thing keeping me down is the broken collarbone. I can move my arm with almost no pain, but the bones are tapping around on each other. I'm hoping they knit back together soon so I can get back to work.
The adapter showed up last week so I'm waiting for the 205 now. Im selling my quads so I'll have plenty of extra cash for the build.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

Solid plan!

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

The np205 showed up the other day. Really nice looking case. Hopefully it works as good as it looks. I'll get pictures when I get some time. I ordered the flex plate and spacer for the older 4l80e since its a pre LS case. Im still thinking Holley #550-613 for the controller since it can control the trans. It's pricey but I think it's the best route since I have no one to tune it local if I go with a gm ecm. As it stands I'm about $2200 into the trans, tcase, and other parts. The engine is another story which will easily top 10k, but that's with a Wegner serpentine kit which is on the list.

I have surgery Wednesday to have a pin put in my clavicle bone so I'll have a few weeks to get back some use of my arm and a few months to get close to 100%. Being hurt blows.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

So I ordered the Wegner front drive kit. I went with the Diamond cut setup. I called Boyd to see about an efi tank and they turned me to AZ performance. They informed me they have done tanks for blazers and suggested a tank that would fit. I measured it up and told them where I wanted the filler neck and that should be here in a few weeks. They cut me a deal on the tank and a new line kit with AN fittings and mixture of hard line and soft line.

My surgery last week went well. I now have a pin in my collarbone and a soon to be scar to add to others. Pain was a bit nasty the first two days but I'm a lot better now. I did crawl under my blazer today to measure and my ribs reminded me they were still broken.
I'll try to get some pictures added soon to make the build more informative.

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

Woot! Pics or it didn't happen :lol:

Re: LS3, 4l80e, Np205 in 1972 Blazer
 

Updated progress.