4.3 vortec to 5.3 ls!

[sierrastepside]

What's up everyone? Let me start of by letting everyone know I got 98 sierra stepside (hence the username) with a tired old v6. I originally planned on converting to v8 and building a new motor but I decided to go with an ls swap mostly because of all the great things I've heard on here and it's newer technology.
So here's the thing I have come across two deals involving 5.3's and I'm having a a bit of trouble deciding in which direction to go so I was hoping to get some advice and help on here. Anyway first one is 2007 aluminum 5.3 and trans with harness and computer with all accessories with 50k on tranny and about 30k on engine for 2100, second there is a 2003 iron 5.3 with 83k miles buts it's a complete pullout exhaust accessories wiring and computer the complete deal for 800. Thing about the iron block it's about an hour drive away. Now I don't plan on doing anything crazy at first just want to install and upgrade later on but what I am wondering is which do you guys think is the better way to and which one would you guys go with? Thanks in adcance!

[Chevydillan]

Do you plan on making your own harness? I'd still probably go with the aluminum one though. The swap from vortec to LS is pretty easy and only requires a few wires to be added to your existing harness anyway. There are always junkyards for any missing pieces. Just my .02 wish I had an l33 and better heads.

[sierrastepside]

I heard it's not that hard just time consuming so I was thinking about giving it a shot...is that what you did? Ok so wiring wise it's pretty easy, How bout the actual swap itself? Aluminum is just better than iron huh...it has 799 heads and I've heard they're the same as 243 I believe, any truth in this?

[Chevydillan]

Yes I made my old harness run the new the 5.3, with some changes to make it look good. It is very time consuming but your right. Not very hard. The first time is always the hardest. As far as the l33 aluminum block being better, I doubt there is really much difference. The weight is a nice factor and the heads are basically 243s so that's pretty good as well. I guess it all depends on your goals really.

[zebra]

the 799s are like 243s with regular valves. if you're planning on boosting, the LM7 will be a stronger block, but the L33 would be nice for weight savings & a little higher compression in a N/A build

[sierrastepside]

Okay so the guy with the iron motor ended up selling to someone local so it looks like aluminum is gonna be my route. @zebra for now just n/a no plans on boosting at the moment so it looks like those heads and motor are good for me. @chevydillan did you use wiring diagrams and pilots for your wiring harness, or what did you use? About how long did you spend working on it?
This a very general question with no single answer but how much does an ls swap actually end up costing? From experience. Without the cost of the motor

[Chevydillan]

I read and bookmarked everything I could get my hands on for a few weeks leading up to the swap. Lextech also helped a ton, I'd suggest pm'ing him. I used my original harness and added the wires that weren't there using the donor harness so I didn't have any cuts or splices. It really was easier than I thought it would be. As for cost, I bought a complete running and driving rolled tahoe so I had everything at my disposal. So, headers, motor mounts, fuel line adapters and the a/c relocation from lextech were really the biggest things. Then there all the little stuff, fluids, filters hose, new gaskets and that kind of stuff. I'd say a guy could easily get it done for 500-800 minus engine. I'm afraid to add up what I have in it so I couldn't say for sure.

[sierrastepside]

Alright thanks, Hmm, that sounds real simple. I'll definitely be sending him a pm once I get to the wiring part. Now did you relocate your a/c because the cross member was in the way? Cause I've heard of people modifying the cross member to make the a/c fit on the ls motors. By the way, did you originally have a v8 or v6 be you did the swap? That's not to bad at all l, I was hoping to stay under 1000 so I might be able to achieve that goal. Otherwise the wife wouldn't let me hear the end of it lol

[Chevydillan]

Originally a 5.7. Lextech's a/c kit lets you keep the original location of the compressor so no modifications are required. I didn't even loose the freon during the swap.

[sierrastepside]

How much is his kit? Correct me if I'm wrong, but on the ls motors the ac goes on the bottom passenger side but on 96-00 motors its on the top passenger side right? Using that kit will allow you to use the same ac lines? I ask cause I am wondering during 80 my ac lines will work since I got a v6