Silverado 4.3 swap to 6.0

[marrell1482]

Hey there I'm planning to swap out my v6 from my Silverado and replace it with a v8 I know my trans will mount up but I was talking with a guy the other day and he said I had to switch my transmission comp? He also said I needed a different comp for the motor when really the one I have just needs to be flashed. Anyone have any input on my transmission issue? Thanks

 

[SubUrbanCamo317]

What year is the truck? If its a older (pre 2000) truck then you may have to swap more than the computer. Generally if its a 2001-2005.5(I believe) you have to get the instumen cluster, the wiring harness, and the computer. GMs trans is controlled through the main ECU to my knowledge. I would say look on some GM truck forums for the best info. Good luck! All the best!

 

[marrell1482]

Thanks I thought I put it up there. It's a 99 and I believe from what I've read as long as the new motor I get is 99-02 there are some odds and ends that are different like motor mounts and a couple other small things. But the computer itself is the same I would just have to flash and tune it. I've looked around some forums and haven't had much luck with this issue maybe just dig some more. But I'm in here every day figured I'd give it a shot. I know the cluster with the 5.3 out of a 2500hd is the same not positive about the 6.0. The forums I have been through are pretty vague honestly majority of them are just about swapping from v6 to v8 not sure if that's much of a difference between the swaps to 4.8, 5.3. And 6.0 but I've found a guide to the general v6 to v8 and it didn't mention anything about the transmission computer.

 

[Mf2racer]

Thought I was on another fourm for a second. I am also Mf2racer over on Ls1truck. You will find all the info you need here. Official NBS 4.3v6 to GEN 3 V8 swap Guide

 

[marrell1482]

Alright it doesn't mention anything about a different computer so I guess I'll find out when I get there haha

 

[marrell1482]

Thanks though!

 

[Mf2racer]

You use the factory pcm. It just needs to have a custom tune loaded on to it.

 

[marrell1482]

That's what I figured idk what that guy was talking about seems like he was just trying to get me to buy stuff haha

 

[Mf2racer]

Yea there is no "transmission" computer on a 99. The Pcm controls everything.

 

[marrell1482]

That's what I thought. But he swore up and down I needed it to swap

 

[96firephoenix]

Consider this: the majority of transmissions that "bolt up" actually don't. They may have the same bolt pattern, but what about the input shaft, or the torque converter. You put a V8 with 2x the torque of your V6 into that V6 converter, and you're looking at a fried converter. Then goes first gear. Then Reverse.

 

[grahamsy2k]

I have a V8, its awesome.

I don't get to use its full power a lot because I try to save gas. But when I need the extra power I forget how much I have.


Good luck.

 

[ATOMonkey]

Consider this: the majority of transmissions that "bolt up" actually don't. They may have the same bolt pattern, but what about the input shaft, or the torque converter. You put a V8 with 2x the torque of your V6 into that V6 converter, and you're looking at a fried converter. Then goes first gear. Then Reverse.

The nice thing about GM is their transmissions are one size fits all.

4L60E is 4L60E regardless of the car its in. Same for the 4L80E.

Just like the old 700R4s were all the same too.

 

[Oliver]

Performancetrucks.net

 

[karl77]

best bet is buy a donor truck and swap the whole powertrain.

would also spend the coins and buy the factory service manuals, as they go in to greater details than the chilton/hayes books.

 

[Mf2racer]

As long as you keep full torque management in the tune a stock 4l60e will live a decent life behind a v8. Pull any tq management and you WILL break a sunshell or burn up a 3/4 clutch pack. Whatever you do I advise do not put a 6.0 in front of a 60e let alone a stock one.

 

[Tactical Dave]

Typically with anything gm and I believe ford and Chrysler you have to change A LOT when going from a 6 banger to an 8.

Many do the swap when the get a do or vehicle and get the service manuals (a guy in ft Wayne sells them cheap and ships them, or at least used to).

It is not a job for a novice wrench turner or for the weak at heart. A lot less work to just get another truck... Only real perk is is insurance savings but remember that if you total it you will get the value of it with a 6 banger and some insurance companies may even drop you and not pay a dime.


Are the motor mounts in the 4.8 the same as the 8's? Will need at minimum a motor and the entire harness and computer, doubt the to converter is the same, have a feeling the radiator is different but not sure.

I know that in say a 99 camaro going from a 6 to an 8 guys just get a donor car and drop the whole front end out and swap it.... Donor truck is the way to go... Lots of little things that you will forget to buy.

 

[remauto1187]

As long as you keep full torque management in the tune a stock 4l60e will live a decent life behind a v8. Pull any tq management and you WILL break a sunshell or burn up a 3/4 clutch pack. Whatever you do I advise do not put a 6.0 in front of a 60e let alone a stock one.

Never heard of "the Beast" sunshell huh? Never heard of a Z-pack clutch kit huh? Never heard of the 4L65e ? Ever even built a 60e? Been inside one?
A 65e is good for up to 500hp and no stock 6.0L is going to be putting out 500hp.

The PCM connectors have to have the same amount of pinouts in order to be reused with the 6.0L. My 99 GMC Sierra PCM is NO GOOD for a LSX engine. There is a spacer that is needed between torque converter and the 6.0l for it work.

LS1tech.com has all the information you will ever need for a swap. There are already people on there that have documented what it took to do their swap to 6.0l.

 

[Tactical Dave]

+1 on ls1tech.com just ignore the clowns and the "how fast do you think I will go" threads that seem constant. I think they have a truck section now.


Don't forget front springs and shocks... A lot more weight up front with the swap.

 

[downzero]

I wish this swap was as well known and documented 6 years ago when I built my 383 stroker. A 6.0 would have great power and would have been much cheaper than the direction I ultimately took.