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A Few Swap Questions

J

jaybaum96

New member
So some of you may know me, some may not. I had a 96 Lumina i had done an l67 swap in, and am now doing just about the same in my 97 GT. I was going to go the turbo route but with school and working full time i decided id go the "more reliable" and money saving route. Just some questions/unclear stuff to me as far as doing the swap in a gp before i begin to gather parts...

1) I am getting a low milage topswapped l36 from a buddy of mine. I am going to get a 98+ harness and pcm, therefore getting rid of the dreaded 97 pcm/wiring. Should i get a 98+ GTP or GT pcm since the motor is topswapped? What changes do i need to make to the harness if i were to get a gtp harness? Any changes at the firewall wiring wise? I know in my lumina i had to change some wiring at the c100 connector..

2) I will be getting a built trans. Currently i have the 4t60 vac trans, so that is another reason i am upgrading my wiring harness, to control the trans. I am either going to do a beefed up 4t65 to keep 3.29's or a 4t65hd. If i do a 4t65hd Do i just simply get 98+ GTP axles? Also, if the trans will be a 4t65hd will it bolt straight to the l36 block/flex plate?

3) Since i will be upgrading the harness and pcm to a 98+, will my gauge cluster/dic still function properly? The only thing ive read up so far is no abs (i can live without it), the temp gauge along with the fuel level gauge will not read correct with a different pcm.

4) Trans lines. I know the 97's had different trans fittings in them. What route must i go with these sense ill be swapping the trans?


I hope i can get some answers and insight, and thanks in advance for the help!
 
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1.) use a gtp pcm, youll need it tuned regardless. the map sensor will need an adaptor. zzp for that.
2.) yes the trans will bolt right up...what year is the trans exactly? gtp and gt driver side axles are the same, passenger side is different, youll need the gtp obviously
3.) try and get a 98-02 GT "trac" button dic and gauge cluster. 97 has tire system on it, i wouldnt use it to be safe.
4.) yes just get the 98-02 lines and fittings
 
1)Yes i know it will need to be tuned. The motor will have some work done to it so a tune is first priority. Could i just get an entire l67 harness and not worry about the map sensor adapter?

2) Not sure what trans i will be using yet. I will stay away from 97 and 03, so it would be a 98-02. And im still unsure if im going the 4t65e or 4t65hd route as of yet.

3) Will any dash wiring need to be changed or will it all be plug and play for the dic and cluster? For the DIC im not to concerned about it even being digital. I have a analog one in my car now and its fine, im just concerned about the trac button..

4) Will do.

Thanks for the fast response!
 
1.)yeah if you can get the l67 harness that would be easiest.
2.)4t65e plus upgraded internals would be nice so you can keep the 3.29s lol
3.) the wiring i wanna say should be plug and play. 97-99 should be the same im sure or till whenever they changed the speedo markings (01 maybe?)
 
Hmm. never knew they changed the speedo markings. I was thinking about getting a special edition cluster, but if the markings will cause my speed to be off, then i wont.
 


HD trans comes with a 258 mm converter which will not bolt to an L36 flex plate.

So you can drill the flex plate for the larger bolt pattern, buy a different flex plate, or buy a different converter.

You'll need the right connectors on the harness for the MAP sensor.

Everything else will be the same.

Might as well leave your harness in place and just swap that one connector.

Not sure if you can put a 98-02 PCM in a 97.

Regardless, the bin file you'll want to use would be a GTP file.

Make sure it has the right settings for the MAF, injectors, and trans gearing.
 
I will be doing a l67 flexplate. My harness does not have the correct trans wiring nor function to control an electronic trans. So that is why i am going to get a 98+ harness and pcm. So im just wondering if any wiring changes must be made at the firewall? Also, how will it perform with the bcm? The guy whos doing my tuning said sometimes his hptuner won't read correctly if the pcm doesnt match up with the bcm.
 
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