LS swap for my 75

[lowrodderchev]

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

[Jonboy]

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.

[68Timber]

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.

[lowrodderchev]

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?

[68Timber]

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.

[lowrodderchev]

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

[lowrodderchev]

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.

[Jonboy]

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

[lowrodderchev]

looks like I'm going to keep searching thanx

[lowrodderchev]

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?

[mcmlxix]

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.

[68Timber]

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.

[lowrodderchev]

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

[68Timber]

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.

[wtrskinut]

Originally Posted by lowrodderchev

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

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.

[lowrodderchev]

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?

[wtrskinut]

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

[lowrodderchev]

Thanx man

[Zoomad75]

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.



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.

[slotard]

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.

[lowrodderchev]

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

[lowrodderchev]

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

[68Timber]

Originally Posted by Zoomad75

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.

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.

Originally Posted by lowrodderchev

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

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

[lowrodderchev]

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.

[lowrodderchev]

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