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LSx K5 Swap Questions

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WOOS1

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I have tried to search swap threads, but have been unsuccessful in my attempts. I am entertaining the idea of swapping a LQ9 into a 1990 K5. I have several questions for those experts out there. The LQ9 will be rebuilt and have a mild/moderate cam. I have access to NOS kits and there could be an occasion to spray a 150 shot.:D Obviously a 4L60E will be the easiest to install, but I am concerned that it will not live long term. The max tire size will be 33" and the truck may occasionally pull a 3K pound trailer. I do not mind spending $3K on a built transmission, but don't want to do that to find out that it will only last a year.

If I do need to move up to a 4L80E to accomplish my goals, what issues must be resolved? I know that the case is longer. I assume that I will have to relocate the T/C rearward to accomendate, but I really don't want to lengthen/shorten the drive shafts. Is there a possibility to push the engine forward? If not, what is the reason: crossmember in the way? Can a new one be fabricated? I read that the Dirty Dingo mounts are good to use. I can get some different mounts thru my work that I may try just to check.
 
RyanB would be the guy to chat with about an LS swap. I don't think he's been around much lately though. As for the trans, the 4L60E should hold up just fine especially with only a 33". The 4L80E is quite a bit longer and would require driveshafts mods or moving the engine forward but i'm not sure how much longer that trans is over a 700R4/4L60/4L60E but I want to say I remember it being about 3" longer. Someone will chime in with the correct info and correct me if i'm wrong.
 
Another quick question on the same lines. With a 4l80e Are there different spacer or TC's or flexplates used? I'm going to be doing this same swap however obviously in my case I have a 4l80e.
 
WOOS1 said:
If I do need to move up to a 4L80E to accomplish my goals, what issues must be resolved? I know that the case is longer. I assume that I will have to relocate the T/C rearward to accomendate, but I really don't want to lengthen/shorten the drive shafts. Is there a possibility to push the engine forward? If not, what is the reason: crossmember in the way? Can a new one be fabricated? I read that the Dirty Dingo mounts are good to use. I can get some different mounts thru my work that I may try just to check.
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Since the 6.0 came from the factory with a 4l80 hooking the engine and trans together is no problem. The dirty dingo mounts are adjustable I have mine set to the rear most position to hook up to my th350. I dont know if moving them all the way forward would be enough to still not move the t/c mount. If you can get a measurement on the length diff between the 4l80 and 350 I can measure the amount of movement available on mounts. I do you that if you move the engine forward at all you will have to swap the engine crossmember. http://www.twiztedengineering.com/servlet/the-46/GM-High-Clearance-Crossmember/Detail This is the only one Ive seen that will clear the engine or you can make your own.
 
texas4x4rebel, what engine/trans combo are you running? Any issues with the cross member installation? Got any pics you can post or send? Thx.
 
WOOS1 said:
texas4x4rebel, what engine/trans combo are you running? Any issues with the cross member installation? Got any pics you can post or send? Thx.
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Im running a 5.3 with a th350 it was a close fit with the crossmember had to trim one small bracket there are pics in my build thread of what I had to trim.
 
Personally I have an advantage in a way. My 91 came with the 4l80e. I'm just trying to make sure it will work in the same fashion as the newer ones or if I must swap in a newer one. I've heard both.
 
texas4x4rebel said:
With that much length diff if you do run the 4l80 your gonna end up moving the trans mount no matter which mounts you run.
Click to expand...

So one could not physically move the engine forward that much even with the aftermarket cross member? I am really wanting to run the 6.0L, but I may just be better off picking up a 5.3L and hoping it will live with the 4L60E.
 
WOOS1 said:
So one could not physically move the engine forward that much even with the aftermarket cross member? I am really wanting to run the 6.0L, but I may just be better off picking up a 5.3L and hoping it will live with the 4L60E.
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If you go with the aftermarket crossmember you can move the engine forward. If you can get a 6.0 for a good deal pick it up you can do hp mods
much easier with the 6.0. It comes with better flowing heads and you can do a much larger cam in a 6.0 than the 5.3.
 
I'm running a 5.3 with a 4l60e and a 241.Yea,your gonna have to refit your drivelines too.
I'm also running 35" tires with a 4.56 gear.
I started with a ORD crossmember but found that it was too close to the pan. Ended up with a Twisted Enginearing one that gives enough room.
Check out my thread.
 
fyi the stock crossmember is crap anyways. thay like to crack with heavy use.

best to get aftermarket anyways and get what you want in the end. :waytogo:
 
I have a 6.0L and a 4L80E in my K5. Both my crossmembers are custom. The trans one had to be redone for the length of the 4L80E and the engine one for oil pan clearance. The engine sits in the stock location with advance adapter mounts which puts the engine pretty far back on the firewall. If your doing that much work reworking your driveshafts should be the least of your worries.
 
WOOS begin the build thread! Looks like tons of info from people on this stuff. If you decide to go for it I'll be following it for sure.
 
texas4x4rebel, I currently have a 6.0L engine that needs rebuilt. Have stock 317 heads. May ditch the truck manifold and stock TB. I really would feel more comfortable with a 4L80E, just not sure I am comfortable with al of the fab associated with that swap. I know that there are some new swap brackets, oil pans, and exhaust manifolds that will be on the market soon that could make this a little easier. Also trying to figure out if I want to run a GM ecu or an aftermarket controller.

74kay5, are you running A/C? What accessory brackets are you running?
 
You won't get any more torque performance out of a Corvette manifold than you will out of the truck one. And torque is really what you want.
Now,if your talking about exhaust maniflods then yes,you need to change them anyway too fit between your frame rails.
As far as the ECM is concerned ,the stock one can be adjusted just as much as a aftermarket one for a little less.
 
The aftermarket ecu is just a gm ecu with the tune changed if I where you I would find a good performance shop local that does alot of vetts and fbodys and take it to them to have the tune done. You will be happier in the end going that route.
 
He is right. Bottom line , do a lot of homework on this. You'll be happy that you do.
This is still a new up coming thing. I learned a lot and am still learning more all the time. More shops are makeing new products for this application. And you'll see that the old smallblock is going to become the flathead ford v-8.
Think about it, to get 400 plus HP out of a LS and still get 20 +MPG for the same price as the old SBC [that you would never get],why would you ever go back?
 
74kay5, are you running A/C? What accessory brackets are you running?[/quote]

Run a stock reprogrammed ECU to control the 6.0L and 4L80E, that will save you a ton of money on a controller and probably work better. Was going to run AC but the box kept getting in my way when working in the engine bay so I ripped it out. The AC compressor was removed and made the engine fit better as well.
 
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