1996 4.3 to 5.3 Swap

[Safariwagon]

New 5.3 Engine!
Empty Engine bay!

Ok, I am under way! I need some help with above questions. LC9 is the 5.3 all aluminum block. I believe LQ9 is the 6.0 litre. Help is much appreciated!

[Jay 8850]

Nice truck! Mine is a stepside too.

The 4.3 accessory brackets will not work, you need the ls truck style brackets. I kept the original alternator and ac compressor in their original locations. My buddy made brackets to keep the ac on the drivers side and a company called Goat Built makes a kit to put the alternator on the passenger side of the engine.

The 4l60e will work, put in the Corvette servo assembly in the trans to crispen up the shifts, will need the nbs style trans lines too, if mine gives out, will upgrade to the 4l80e

I used a harness from a 2000 truck and a 411 pcm from a 01 6.0. Get the pcm reflashed ahead of time to remove the vats and whatever else you may not use.

Will need a radiator from a newer truck along with the coolant bottle.

[Safariwagon]

Thanks for the reply! I was beginning to think I wasn't going to receive much help. What motor ar eyou using? Is it an LC9? I was thinking of going for the Nelson wiring harness/Tune to simplify things as wiring is not my thing and I need simple. Plan on having the 4l60E rebuilt since it's a pain to pull it out later, so I will do the reccomended upgrades. Forgive me but what is a NBS style tranny line? Guess I am accessory and radiator shopping at the bone yard soon. That's what I love about these trucks. Everybody is after the LS car stuff but the truck stuff is cheap and should work on the older trucks!

[Chevydillan]

You don't need a NBS- new body style 99-07. Radiator. The stock radiator works just fine, you may want to upgrade to a v8 radiator though and you can use a stock fan shroud but it's a good time to switch over to electric fans. They can add the needed wires when they build the harness.

[droopyzda1]

I used ebay electric fans for my 5.3 swap in my 1994 obs. I trimmed the fan shroud a bit and retained the original V6 4.3 radiator. U can rewire the original uncut LS harness using the lt1swap.com website. On the same site he removed my vats for $75 with about a 7-10 turn around time. I emailed him a few weeks later after I finished the swap cause I had a few bugs and he keeps record of it. He was able to go back and verify what he tuned on the pcm.

[Safariwagon]

I am a little slow getting going here. Seems several places make the engine mounts. Looking to retain the factory A/C so I am checking into that. One thing I haven't been able to find much information on is the transmission. Aas seen in the above pics it's the 3 piece 4l60E. Can I just switch the bellhousing over to the "LS" style or do I still need some kind of adaptor? I've read varying opinions on this. Some say input shafts are different and torque convertor spacing is different, etc. Anyone here done this yet?

[Chevydillan]

You'll have to use the flat 6.0 flex plate with a spacer and probably elongate the torque converter holes. Thats the only way that trans will work behind the ls engine. It's cheap and easy. Factory a/c is easy to keep as well, not sure what compressor your truck has but there are kits out there to keep it. I used dirty dingo DD2550C mounts. Worked perfect.