Engine and computer question.

[89obsSB]

I have a 97 c1500 with a 305 and I have an opportunity to get a 99 c1500 with a 350 for 300 bucks. both are 4l60 trucks. Would the computer in the 97 work if I swapped the 350 into it? Or would I need to change the computer with the engine and what all else would be involved?

 

[Erik the Awful]

Yes, it will work. Will it work well? You'd need to reprogram the computer or swap to a later computer that's easier to tune.

 

[df2x4]

Easiest option IMO would be to have the '97 PCM tuned for the 350.

 

[89obsSB]

Easiest option IMO would be to have the '97 PCM tuned for the 350.

Well the truck the 350 is in is complete and has everything. Would I be able to swap the computer engine and harness with no tuning?

 

[89obsSB]

Yes, it will work. Will it work well? You'd need to reprogram the computer or swap to a later computer that's easier to tune.

If I buy the truck I’ll have the computer as well. It’s a complete 99 c1500 with 4l60. Mine is a 97 c1500 with 4l60

 

[TexasRebel]

'99 C1500 with a 350? Didn't know they made the half ton 2wd gmt400 in '99. Engine will swap right in. One thing I'd do different though is go ahead and swap it to a 0411 pcm. You can get them on ebay for a little over $100 and the repinning isn't too bad as long as you find the correct wiring diagrams. The 0411 is a way better pcm setup and allows for easier tuning.

 

[df2x4]

Well the truck the 350 is in is complete and has everything. Would I be able to swap the computer engine and harness with no tuning?

Probably, but I'm not sure if there were any little differences between the '97 and the '99 that would cause issues regarding other equipment on the truck. If I were you, I'd download the '97 and '99 service manuals here and compare pinouts for the various connectors. This would help prevent you from running into anything unexpected and give you an opportunity to compare things in general. Which leads me to the reason for my original post...

If the '97 harness for the 305 setup is basically the same as a '97 with a 350 (I'm betting it probably is minus the different O2 sensor configuration and maybe some other little bits) it might be easier to leave it in place and just add what you need, then tune the '97 PCM for the 350.

Speaking of O2 sensors, do you have the exhaust off the '99? The 305s shared an exhaust with the V6 trucks and only had one cat IIRC, so they have three O2 sensors vs four on the 350 setup.

 

[89obsSB]

Probably, but I'm not sure if there were any little differences between the '97 and the '99 that would cause issues regarding other equipment on the truck. If I were you, I'd download the '97 and '99 service manuals here and compare pinouts for the various connectors. This would help prevent you from running into anything unexpected and give you an opportunity to compare things in general. Which leads me to the reason for my original post...

If the '97 harness for the 305 setup is basically the same as a '97 with a 350 (I'm betting it probably is minus the different O2 sensor configuration and maybe some other little bits) it might be easier to leave it in place and just add what you need, then tune the '97 PCM for the 350.

Speaking of O2 sensors, do you have the exhaust off the '99? The 305s shared an exhaust with the V6 trucks and only had one cat IIRC, so they have three O2 sensors vs four on the 350 setup.

I can probably get access to those service manuals at work. I’m a tech at a GM dealership. I’ll see what I can find.

 

[89obsSB]

Probably, but I'm not sure if there were any little differences between the '97 and the '99 that would cause issues regarding other equipment on the truck. If I were you, I'd download the '97 and '99 service manuals here and compare pinouts for the various connectors. This would help prevent you from running into anything unexpected and give you an opportunity to compare things in general. Which leads me to the reason for my original post...

If the '97 harness for the 305 setup is basically the same as a '97 with a 350 (I'm betting it probably is minus the different O2 sensor configuration and maybe some other little bits) it might be easier to leave it in place and just add what you need, then tune the '97 PCM for the 350.

Speaking of O2 sensors, do you have the exhaust off the '99? The 305s shared an exhaust with the V6 trucks and only had one cat IIRC, so they have three O2 sensors vs four on the 350 setup.

It’s a complete running truck so the exhaust should be there. I have not pulled the trigger on buying it yet.

 

[89obsSB]

'99 C1500 with a 350? Didn't know they made the half ton 2wd gmt400 in '99. Engine will swap right in. One thing I'd do different though is go ahead and swap it to a 0411 pcm. You can get them on ebay for a little over $100 and the repinning isn't too bad as long as you find the correct wiring diagrams. The 0411 is a way better pcm setup and allows for easier tuning.

It may be a 98. I have not actually looked at it in person yet. It belongs to my father in laws neighbor. He said the neighbor told him 99. I’ve only seen in person 4wd 99 gmt400s. All I know is it is for sure a gmt400 and that it runs and drives and I can get it for cheap.