LS swap for my 75
 

I notice my 75 blazer is getting a little tired. I debated back and fourth about getting rid of her and getting a new truck but after 2 people saying "get new truck" and like 20 saying "your stupid if you sell her" guess what I'm keeping her. right now I'm running a 350/350/203 part time conversion. I'm going for a LS swap 5.3 still debating on a 700R4 or a 4L60E transmission. the other thing is the 203. its fine now so do I keep it or get a 205 since I have it apart? and if I do a 205 is there a certain year I need to look for. I like having the option of occasionally towing if I have to which is why I want a bigger transmission plus if I'm putting a LS I'm defiantly going to want to be doing a lot more long distance trips so I'm guessing the overdrive is helpful on the freeway. so any input guys? thanx

Re: LS swap for my 75
 

The overdrive will really shine on the highway, but the 700R4 and 4L60e have a lower 1st and 2nd gear than the TH350 you currently have. If you are going LS, I would use the 4L60e and let the PCM control it as well.

Re: LS swap for my 75
 

I'd set the 203 aside with the stock engine/trans for selling or another project. The 205 is great, but I'd probably run a 208. There's plenty of them out there and it's plenty stout. Put that money towards the harness.

Re: LS swap for my 75
 

Thanks for the responses guys. Bruiser will the 208 be ok with my 4 inch lift and 35 tires? And would anyone have a suggestions as far as what year of transfer case would be my best bet?

Re: LS swap for my 75
 

Unless ski-me has upgraded his, he's running 35's on the stock 208. That's what's in my 85 behind the 6.2/TH400, I'm running 2.5" lift and 33's. You'll be fine. I don't think any one year is stronger than the other. Side benefit, you'll be able to run a shifter and components from an 80's truck, should be easy to find and cheap.

Re: LS swap for my 75
 

Guess I'll be hitting the junkyard today searching for a 208 or 205

Re: LS swap for my 75
 

does $2,500 for LS 5.3 and 4L60E computer to sound about right? found a guy that is selling it but he's also 2 hours away. has about 109,000 miles on it. or should I keep looking.

Re: LS swap for my 75
 

Sounds high. That is around $1000-1500 with pedal, TAC module, wiring, ECM, and all accessories around here.

Re: LS swap for my 75
 

looks like I'm going to keep searching thanx

Re: LS swap for my 75
 

Found another motor only no accessories or wiring my buddy said he could get it for around $400 does anyone know if I run the carb intake with coil for the 5.3 will I still need the harness?

Re: LS swap for my 75
 

MSD makes a box to control a carbed LSx motor... but it will not control the transmission. Also, in my opinion, the main reason to swap to LSx is EFI and the OD transmission. You are forfeiting that swapping to carb...
http://www.msdignition.com/Products/...oth_Crank.aspx

Here is a complete wrecked truck for sale in Bakersfield...
http://bakersfield.craigslist.org/pts/5346840239.html

PS: Stay away from 1999 and 2000 truck motors. The first two years had issues. I would skip 2001 just to make sure and look for 2002 or newer.

Re: LS swap for my 75
 

I don't think I'd go to the trouble to fit an LS in there just to carb it. A new goodwrench motor would be easier.

Re: LS swap for my 75
 

I'm starting to think the stock motor would be easier. I'm reading up as much as possible but still trying to figure clearance issues, transfer case adapters, and gas pedal.I figured fir a minute I would run a 700R4 to the 5.3 but iv heard there a bad combo. I may just fork out the money and buy a 383 and call it a day

Re: LS swap for my 75
 

It would be, for sure. But then again those guys participating in the LS Challenge are swapping them in just over an hour. So you know it's not that hard, just a matter of figuring out what you don't know and what you need.

Re: LS swap for my 75
 

I have a 75 2wheel drive that I was debating a LS swap or 383 Stroker. Ended up going with the 400 hp+ 383 Stroker and a built 700R4. Real happy with the set up. Good luck either way.

Re: LS swap for my 75
 

Why'd you have to show me that beautiful engine compartment. Lol think I've made up my mind just stick with a small block carbureted motor. Where did you get yours at wtrskinut?

Re: LS swap for my 75
 

Lowrodderchev, I sent ya a pm.
Posted via Mobile Device

Re: LS swap for my 75
 

Thanx man

Re: LS swap for my 75
 

Getting close on my 5.3 swap. DrityLarry's done most of the heavy lifting for me, but I did all the research on the swap since neither of us had done the LS stuff before. He's done 8.1's but the GEN III stuff is a bit different due to the change in engine mounts but as far as the EFI and electronics go it was the same as his 8.1 swaps.

Here's a little sample where we are at on mine.

https://scontent.fsnc1-1.fna.fbcdn.n...67&oe=56DE67FA

Carb isn't the way to go with a LS engine. Yes you'll get it running, but the advantage to this swap is the EFI. I kid you not this thing starts like any modern fuel injected truck. Twist the key and go. My 75 with it's 350 and quadrajet never started like that. I had the q-jet dialed in well too. Summertime it was fine, but once it got cold it sucked and would take 20 minutes to warm up. Driveability is better, fuel economy is better and it's not as overwhelming as one might think.

As far as mating a LS engine to a 700r4 it's not a big deal either. I used a Bowtie overdrives TV made EZ kit. They make a kit specific to the Vortec truck intake or the Vette intake. Instructions are clear and the cable/bracketry takes the guesswork out of the cable geometry.

Big tip. Save yourself a headache and get a custom harness rather than reworking a factory harness.

A simple option is running a system that uses an MEFI4 controller. It is a simplified setup and the same controller used on the Ramjet crate engines. Painless sells a harness and MEFI4 kit as well as a couple of others. It's not as complex in the wiring and it doesn't require efilive to tune.

This is my first one and I'm sold. If another 5.3 or 6.0 falls in my lap it might end up in my Nova.

Re: LS swap for my 75
 

I agree that if you're doing an LS swap you should stick to EFI.

Depending on how much towing/hauling and how hard you're beating on it, there's always the option of a 3/4 ton setup. 6.0/4L80E, I don't recall what transfer case they use but I suspect it's adequate. Gearing is a little closer than the 4L60E, which has upsides and downsides.

Re: LS swap for my 75
 

I'm going to stick with a small block. either a 383 or a 350. I'm going to start shopping around tomorrow. call a few local shops see what they got. thanx guys for the imput

Re: LS swap for my 75
 

Ok scratch my last post. I was surfing Craigslist found and picked up a 2001 ls 5.3 with 4x4 tranny all the parts computer everything $1100 has 180,000 miles

Re: LS swap for my 75
 

I can't believe Larry didn't talk you into an 8.1. Looking good though, he always makes them look like it was done at the factory.

Good deal. The fuel injection will make it worth the effort.

Re: LS swap for my 75
 

Thanx bruiser I'm looking at February or march to put it in. January will be spent cleaning it up spray some orange on it and figure out what I need as far a transfer case, adapters and wiring redone. Then I'll take a week off and go town.I'm going to continue this thread with pictures of what I'm doing to it.

Re: LS swap for my 75
 

any suggestions on what year of 208 to run to a 4L60E 4x4 transmission? I'm hoping not to break the bank on a adapter

Re: LS swap for my 75
 

Bruiser- We had talks about an 8.1. Fact was the engine that is in the polar bear came from my garage. My budget really wasn't jiving with the expense, harness and controller, ect. So we horse traded and I got the MEFI4 controller and custom harness to run the 5.3 on, he got the engine. Hindsight being 20/20 knowing what I've spent so far on the 5.3 the 8.1 swap might be a wash. Then again my 5.3 was a take out of a customer's truck that had us install a 5.3ho GM performance crate. So no cost out as he didn't want it. Mine has room to grow with the 5.3 though as a 6.0 isn't hard to find either.

Getting back on track, if the OP is planning on using the PCM and wiring from the donor truck, using a 208 isn't going to get the vss signal needed. Go look for a pass side drop 241 from a 90-91 Blazer or Suburban. Specifically, a 27 spline input to match the 4L60e. That will have the correct VSS tone ring and sensor on the output of the t-case to provide the input needed to the PCM. The 241 will bolt right up to the 4L60e too.

Re: LS swap for my 75
 

sweet thank you I'm going to start hunting tonight thanx again

Re: LS swap for my 75
 

Thanks for the correction.

Re: LS swap for my 75
 

So was pulling the harness from the motor and I'm having a hard time removing the plug that's were the shifter arm is. Theres 2 plugs neither one of them will budge. Any suggestions?

Re: LS swap for my 75
 

Its this plug

Attachment 1477821

Re: LS swap for my 75
 

Looks clean no

?Attachment 1477822

Attachment 1477823

Re: LS swap for my 75
 

The connectors at the range switch are a little stubborn, but with a small pocket screwdriver or pick they should come free. The top connector, pull the blue clip out of the connector. Then lift up on the grey loop that is just to the left of where you pulled the blue clip from and it should release. Remember these are weatherpack connectors so the rubber gasket inside might not make the connector pop right out, you might have to work it side to side to get the gasket to release. The lower white connector just needs that bail end pulled up over the lock to release. Still, work the connector once it is loose from side to side to finally pull it out.


Heads look clean! Good Score!

Re: LS swap for my 75
 

Man I'm full of questions and a really appreciate all your guys help. So if I switch to a 241 case will I have to modify my cross member? If so what transfer case would you recommend to use to avoid modifying the cross member thanx again

Re: LS swap for my 75
 

A heat gun will help loosen the glue GM put in there. Works like a charm! Nice swap!

Re: LS swap for my 75
 

I'm not sure of the specifics on mounting location difference from the 205 you have to the 241. The beauty here is if it's further back on the 241 vs the 205, just move the crossmember back to adjust. Worst case, get the 241 crossmember from the same truck you got the 241 from. At most you might need to drill a couple of holes in each frame rail to either slide the old one back or fit the 241 crossmember in.

Re: LS swap for my 75
 

how does $413 for a NP241 sound? or should I keep looking? not sure what they usually go for

Re: LS swap for my 75
 

It's a little high, compared to the one I picked up to replace my fubar'd 241. Got mine at a local boneyard for $220 or around there. Is that one a VSS version from a 90 or 91? That's the only two years you can shoot for. Oh yeah, go 1/2 ton only too. I thought I did and the one I picked up was a 32 spline input from a 3/4 ton with a th400. We didn't notice the difference until after we put it back in and we didn't have park. Park didn't work because the 27 spline output fits just inside the ID of the 32 spline input without touching a thing.

Look on car-part.com and search for the t-case with a 91 suburban v1500 in your area. I'm sure somebody will have one. That's how I located mine.

Re: LS swap for my 75
 

Thanx I'll check them out in not having any luck around here

Re: LS swap for my 75
 

So I found a transfer case hopefully the right one the numbers,are
241c
1561 4199
116 903
272

Sound about right?

Re: LS swap for my 75
 

Thanx Zoomad75 looked up that website found a np241 for $180. It 3 hours away but a buddy of mine is heading that way for vaca so he volunteered to.pic it up so now I need a shifter and crossmember

Attachment 1485003