Hello, I need your opinions. I have a beautiful 1989 GMC 1500 all lowered, painted and a cool interior but it still has stock power. 305 tbi only 99k original miles, 700r4 TV cable model, 2 piece driveshaft, 10 bolt 3:73 posi rear end. I would like more horsepower!!! I have a good running Chevy express 3500 with a ly6 4l80 combo with 144k which could be installed with alot of work. I have up to $7500 to spend but want to make this journey simple and fun with a finished truck that's reliable and enjoyable. Not a wrenching nightmare! I just want to lay some posi!!. I really don't have any access to a ls tuner guy or motor builder. Not close at least. I'm a good wrench though. What would you guys do????? Upgraded 350 Tbi crate motor (easy install and get to keep all gauges and cruise) , 383 crate motor (more work but not to much more. Will lose some options) or freshen up the Ly6/4l80. Lots of work and power. Or just leave the truck stock and cruise it!!
I need mental help!!! What should I do?
- Thread starter Maddmatt
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Sean Buick 76
I'm Awesome
I dont think you could possibly regret a well done LS 6.0 swap especially with the 80E. The problem is all the details add up with so much time and effort that it’s just a big ball of wax.
It’s a tough call but I don’t really advise and part measures! Ponder and then commit, dont let it get stuck on jackstands. Either leave it alone and drive it 100,000 plus more miles miles in gutless TBI peace or go all out and do the LS swap but only once you have the time and coin to do it swiftly.
It’s a tough call but I don’t really advise and part measures! Ponder and then commit, dont let it get stuck on jackstands. Either leave it alone and drive it 100,000 plus more miles miles in gutless TBI peace or go all out and do the LS swap but only once you have the time and coin to do it swiftly.
Komet
I'm Awesome
They will all be lots of work and take all your money, so build what you want to end up having and working on. If you don't want to do any tuning whatsoever, I'd recommend no swap at all.
Cam, springs, and a gasket refresh on the LY6 with a Terminator X Max sounds like a pretty good time to me but I may have a warped perception of fun and easy.
Cam, springs, and a gasket refresh on the LY6 with a Terminator X Max sounds like a pretty good time to me but I may have a warped perception of fun and easy.
Drunkcanuk
I'm Awesome
Option paralysis is real!!! Lol
If it were mine, and just a cruising machine for medium effort, I'd rip guts out of the van and transplant into the truck.
There is so much info on LS swaps into these trucks it's almost foolproof. No real need to tune other than the VATS and O2 sensors if needed. Unless you wanna start playing with cams, turbos etc. But putting a 6.0 in place of a 305 will feel like adding a supercharger to the 305.
Going with a 4L80 would necessitate the need for a shortened driveshaft.
Toss in a posi of some sort and enjoy.
But I'd only do this if I had another daily driver as it will take time for sure.
If you want "easy" and good return on your time and effort, drop a crate 383, and a upgraded EFI system like an Edlebrock or Holley.
Then you have to worry about grenading the trans.
The below playlist has a ton of information especially with the wiring.
If it were mine, and just a cruising machine for medium effort, I'd rip guts out of the van and transplant into the truck.
There is so much info on LS swaps into these trucks it's almost foolproof. No real need to tune other than the VATS and O2 sensors if needed. Unless you wanna start playing with cams, turbos etc. But putting a 6.0 in place of a 305 will feel like adding a supercharger to the 305.
Going with a 4L80 would necessitate the need for a shortened driveshaft.
Toss in a posi of some sort and enjoy.
But I'd only do this if I had another daily driver as it will take time for sure.
If you want "easy" and good return on your time and effort, drop a crate 383, and a upgraded EFI system like an Edlebrock or Holley.
Then you have to worry about grenading the trans.
The below playlist has a ton of information especially with the wiring.
xc_hide_links_from_guests_guests_error_hide_media
Sean Buick 76
I'm Awesome
Good info Canuck! There really isn’t any need to modify anything in the LS computer except disabling a few things but that’s dead easy.
I only suggest these swaps when you have a complete donor vehicle to pillage. If you take your time and both label everything and take lots of photos then it’s an easy job to move the modern power into the OBS.
I only suggest these swaps when you have a complete donor vehicle to pillage. If you take your time and both label everything and take lots of photos then it’s an easy job to move the modern power into the OBS.
Hello other lowered ECLB owner. Your truck looks really great.
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someotherguy
Truly Awesome
Dropped ECLB's for the win! 
Sorry.. had to get that out of my system
Your '89 looks great! My opinions on the horsepower situation:
1. That 6.0/4L80E is probably your most direct option for more power. The 144K on the clock could be hit or miss at that point - it might be fine forever, it might also be wise to rebuild both while they're out, but that combined with the needed parts for a swap, would likely break your budget. A direct swap without cracking them open "might" be OK; lots of people take that gamble.
2. 305 to 350 TBI probably wouldn't be enough to satisfy. You'd notice the difference but would likely be unhappy you didn't go further. You'd have a lot of spare coin left, tho..
3. 305 to 383 I would only recommend if you have access to someone that is good at tuning the TBI system, which seems like you don't. A lot of money and effort could be spent here to end up with something that doesn't run right and won't produce the power it should.
And regardless of which route you go - 6.0 or 383 - you WILL need a stronger rear axle if you plan on beating on it. That 8.5" 10 bolt will let go. Look into the 9.5" 14 bolt swap.
Richard
You must be registered for see images attach
You must be registered for see images attach
You must be registered for see images attach
You must be registered for see images attach
Sorry.. had to get that out of my system
Your '89 looks great! My opinions on the horsepower situation:
1. That 6.0/4L80E is probably your most direct option for more power. The 144K on the clock could be hit or miss at that point - it might be fine forever, it might also be wise to rebuild both while they're out, but that combined with the needed parts for a swap, would likely break your budget. A direct swap without cracking them open "might" be OK; lots of people take that gamble.
2. 305 to 350 TBI probably wouldn't be enough to satisfy. You'd notice the difference but would likely be unhappy you didn't go further. You'd have a lot of spare coin left, tho..
3. 305 to 383 I would only recommend if you have access to someone that is good at tuning the TBI system, which seems like you don't. A lot of money and effort could be spent here to end up with something that doesn't run right and won't produce the power it should.
And regardless of which route you go - 6.0 or 383 - you WILL need a stronger rear axle if you plan on beating on it. That 8.5" 10 bolt will let go. Look into the 9.5" 14 bolt swap.
Richard
Just run what you got appeals very strongly to my lazy side.
Need mental health and you came here? Boy, you screwed up!
If the Express van runs good, I'd leave it alone and use it. Put a crate 383 in the C1500.
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