5spd '89 C1500

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05-09-2010, 12:03 PM
gl18rider

5.7 LS1/T56 swap for 305/5spd '89 C1500

Hi,
I've been scouring the pages at this site and hopefully absorbed a lot of the information. Thanks to all the contributors. I may have missed some as I still have some questions. It seems most are doing automatics? Has anyone done the T56 and have feedback?

The donor engine/trans/PCM (whole enchilada) is from a 2000 Firebird (I haven't seen it). Things I've learned, and some questions:

Wiring harness: it should be with the LS1. Either hack it up, or aftermarket.
Engine mounts: after market adapter plates
Exhaust: use stock manifolds
Fuel pump: replace with Delco or Walpro. If the LS has single rail, use wix as regulator.
Gauges. Oil pressure- get adaptor for old sending unit. (S&P?)
Coolant temp - I've seen different responses. Some mention 3 wire sending unit, others indicate port on passenger side head and use old sending unit. Does the 3 wire sender work with later gauges and the '89? I'd prefer the 3 wire unit. Will it work?
PCM: Sorry, not completely clear here. It sounds like I remove the original and use the LS1 PCM and get it reprogramed. I haven't looked at the original PCM so I'm not sure of the number of connectors. Will these all be replaced by the LS harness or will there be some LS harness connections and some original connections? I don't quite get the merging of the harnesses.
Radiator: can I use the stock one with electric fans? I haven't seen any references to a part number for fans.
Oil pan: LS1 from Firebird?

Regarding the 5 speed (Getrag). Does anyone know if the VSS with it is compatible with the T56?

Can you please confirm my undstandings and hopefully answer some questions?
thanks for the help
-gl18rider
05-09-2010, 04:51 PM
92 6.0

I didnt do a manual swap but as for some of your questions:
gauges: Yes get an adapter for the factory oil pressure gauge, and on the coolant temp when I first done my swap I used the 3 wire unit but was told it wasn't as accurate with the obs gauges so I tapped my water pump and put in the factory one for my truck. But my gauge reads the same as the 3 wire unit did.
Pcm: I removed my 92 ecm as its not needed. you only need the one for the ls1.
Radiator: Yes you can use your stock one. I swapped mine to 1 ton rad and installed the 05+ efans.
And the vss in the t56 is the only one you need you dont need the one out of the getrag. as the t56 one is going to be the right one for the pcm.
Hope this makes sense.
05-09-2010, 11:36 PM
low91

Unless your on a tight budget I would use these instead of the stock manifolds.LS1 TRUCK - Schoenfeld Headers

I used the three wire sensor and it seemed to read right where it should besides factory gauges aren't that accurate to begin with. If you do use the three wire sensor method you can use the TPS sensor pigtail from your current TBI unit. Also one thing I don't like about the water pump taping method is that what if your water pump goes out and you don't have a way to tap the replacement right away? Gonna be running without knowing how hot your engine is for awhile.
05-10-2010, 05:01 PM
flattopwill

Quote:

Originally Posted by low91

Unless your on a tight budget I would use these instead of the stock manifolds.LS1 TRUCK - Schoenfeld Headers

:thumb:

Looks like you got your info straight. The old ecm can come out and go in the trash. I sold mine with the old motor.
For gauges, I recommend tapping the oil cooler block off plate for the oil pressure and using the obs sending unit. Get the coolant temp sensor adapter from S&P and put it in the passenger side head.
05-10-2010, 05:39 PM
gl18rider

Thanks for the responses.
I think I'm good with the coolant and oil now.
What about the speedo?
05-10-2010, 05:55 PM
flattopwill

Well, hopefully someone will correct me but It's a bit unclear with the 88-91 speedos cause they have the DRAC built into the gauge cluster and it's hard to access the wires. Here's how to do it on '92+ - http://www.ls1truck.com/forums/lsx-t...ol-wiring.html
If you just want it to work then just splice into the new vss wires and connect the old vss wires going to the cluster and it will work but is not tunable by the ECM for gear changes, tires sizes etc.
05-11-2010, 09:50 AM
tmjoki

I am in the middle of the swap now on my 89 and i recommend getting the mounts that shift your engine back 1-2 inches. i bought the transdapt mount 4572 and the exhaust manifold on drivers side is so close to the rear brake lines the flange wont make it on. i am just going to weld and refab a second plate to my transdapt mounts.
05-11-2010, 11:15 AM
gl18rider

Quote:

Originally Posted by tmjoki

I am in the middle of the swap now on my 89 and i recommend getting the mounts that shift your engine back 1-2 inches. i bought the transdapt mount 4572 and the exhaust manifold on drivers side is so close to the rear brake lines the flange wont make it on. i am just going to weld and refab a second plate to my transdapt mounts.

Can someone recommend which mount would provide the setback?
05-11-2010, 01:11 PM
low91

Quote:

Originally Posted by gl18rider

Can someone recommend which mount would provide the setback?

Here ya go.
LS1 Conversion 1" Set Back Motor Mount Adapter Plates : eBay Motors (item 280500206464 end time May-29-10 23:07:35 PDT)
05-11-2010, 03:44 PM
gl18rider

Thanks for the setback info and link. I did more research and talked to S&P. They had some interesting feedback. To start with, he thought the non-setback should work. He said it depended on the exhaust manifolds. TMJOKI, what year is the LS1 your putting in?
The other interesting approach he had was to keep the original computer for ABS, speedo, etc. I thought everyone was ditching their OBS PCM's and just using the new one? Is there any reason the new PCM would need the speedo if I have manual transmission? I thought I had a decent handle on the computer direction, but now I'm rethinking it.
05-11-2010, 05:29 PM
coastsidekid

Quote:

Originally Posted by gl18rider

The other interesting approach he had was to keep the original computer for ABS, speedo, etc. I thought everyone was ditching their OBS PCM's and just using the new one? Is there any reason the new PCM would need the speedo if I have manual transmission? I thought I had a decent handle on the computer direction, but now I'm rethinking it.

Im curious if i need the computer or not too. Not quite sure on what exactly the computer controls
05-11-2010, 08:29 PM
tmjoki

i got a full 5.3l setup from a 99 pickup. i know its not a true ls1 . From what i have been reading those dirty dingo mounts look good, but the ones on ebay are really cheap and look great. i have problems getting them in canada and shipping time is terrible so that is why i am going to just make something work.
05-12-2010, 06:20 PM
92 6.0

I also got rid of my stock computer but mines a 92. I have a buddy that just put an 8.1 in his 90 model but upgraded to a 92-94 guage cluster.
05-12-2010, 11:51 PM
flattopwill

Schoenfeld was very specific that I used these mount plates and that if I didnt and had fitment issues they couldnt help me.
http://i557.photobucket.com/albums/s...s/DSC01510.jpg
Im not saying others wont work but these definitely do. And, if you arent going to run the Schoenfeld headers then what Schoenfeld says is irrelevant.
Im not sure about using the old computer for ABS because my truck is too old for ABS but you dont need the old computer for speedo.
05-13-2010, 10:13 AM
gl18rider

Thanks. I'm leaning towards the Schoenfeld headers at this point, so I'm also looking at these mounts. Did you use the Moroso mounts or stock cup mounts?
I haven't seen many that are putting in the T56, so hopefully it'll fit fine. I wasn't sure if the trans is going to affect which mounts.
05-13-2010, 11:31 AM
flattopwill

I used stock cup mounts. Im not sure about the t56 length or width but ill tell you im using the mammoth 4l80e and everything fits fine but im sure the crossmember location will have to be modified for the t56 anyway.