So i've had it with this old 305, and i want to do a 5.3. i found one the right price, that was the easy part. I'm gonna use my factory 5 speed, but does anyone know if painless makes a wiring harness so i can still use the 5.3 injection and coil on plug design? or am i better off using the factory wiring from the truck that had the 5.3? I could go back to a big holley carb and HEI, but a whole lot of the 5.3 power is drawn from the electronics and injection, so it can't hurt to try that first. Any thoughts and input would be greatly appreciated, thanks

The stickies at the top have all the info you'll probably ever need and I suggest taking a good long read through it all beforehand. Anyways, I believe Painless does make a harness (~$750 I think), I've also heard a lot about Speartech, which has about the same prices. With the factory harness, you'd have to do some mods (wiring) to make it work perfect although it is cheaper. If you go carb, which many go away from because as you said it gets rid of a main LSX component/ advantage, the only thing I know of that will work, is the Edelbrock intake/ MSD ignition box combo for like $700. A note about using the truck engine though (which you'll find out when you read the stickies) is I've read that truck accessories/ intake/ oil pan won't fit under the stock hood/ clear the k-member. You'd need to make room with a cowl hood or like many others do, change everything to F-Body stuff, among many other little things. Good luck with whichever route to go!

thanks for all the info, i did think about it fitting under the hood, but i guess i figured id cross that bridge when i come to it, at the risk of sounding retarded- what/where are these stickies that you referred to? im new to this forum and i really dont know what they are...

Welcome aboard thirdgen.org.

"Stickies" are in the top section of each forum. The 5.3 is in the LSx family, so you need to read the LS1 swap sticky http://www.thirdgen.org/techboard/lt...third-gen.html (LS1 into a third gen Swap Guide) .

You are going to need f-body oil pan et al, f-body accessories, and f-body or Vette intake.

I can't see putting a carb on one of these engines, especially one regularly street driven. But, to each his own.

thanks bro, i did find it, sounds like a crap ton more work than i anticipated, stuff with the tranny too, i might be better off going old school and building a healthy motor for it that way, i know thats in my skill range, i just thought it might be cool to have a new motor in one...

I thought the same thing. I was all into doing the swap, read all the stickies and now I decided against it for now. Still a new fairly new swap, a lot of people are doing it though so hopefully prices will drop sometime soon.

I'm looking to do this kind of swap in the next year or so. I don't have the money to get everything right this moment and want to get the car running sometime before the fall comes, so I'm going with a basic 350 for the time being. If you have the time and money to not rush it, the genIV motors are the way of the future. If you've never done an engine swap, I wouldn't recommend it as your first try.

I think the swap is well worth it, I have owned built 355-406 3rd gens, even a few BBC cars and nothing beats the airflow/power of an LS motor IMO.

I was always amazed by their power/ mpg ratio. I see a lotta people making awesome power and still getting pretty decent mileage. That combined with their reliability makes for a solid engine. I haven't done the swap myself, but yes, it sounds well worth the money.