Thread: A ton if Questions for my upcoming top swap

As title states, i've got some questions before i actually do the work, I took an entire week off of work, but I hope to finish in 1-2 days, anyways on with the questions:

1. I bought head studs, how tight into the block do I screw the studs, and what should I torque the nuts to

2. I bought a HP tuners and plan on running the L36 in injectors for now(so I can get it up and running before I start cutting and splicing fuel injector wires) Is this ok?

3. What should I set the base timing to in my GT pcm, or should I just flash an entire GTP bin and start from there???

4.Should I coat the head gaskets with anything before assembly?

5. The top swap setup I bought only had bolts for the belt pullyes, are the UIM bolts on a L36 the same as the stock supercharger bolts on a L67

6. Does anyone have a good picture/diagram of the L67 vacuum routing?

7. An tips or suggestions before I start?

Thanks in advance for any answers

Oh, and I bought:
Please tell me if I missed anything

1xNGK Spark Plugs
Model:TR6
1xThermostats 180*
1xComp Cams re-usable rocker bolts
1xHPTuners VCM Suite
1xL67 Swap Kit
1xSerpentine belts
Size:667
1xNeedle bearing grease
1xinjector O-rings
1xHead Studs for the 3800
Option 1:Roll of Teflon tape
1xCrankshaft bolt
1xCoolant elbows
Model:Upper and Lower
1xIntake gasket
Model:Aluminum
1xLower intake O-rings
1xSupercharger gaskets
Model:Garlock L67
1x Intake end cap gasket
1xThrottle body gaskets
Model:Rubber reuseable L67
1xalternator bracket
Year of your car:99+
1xZZP supercharger oil OEMscOIL

Head gaskets, exhaust manifold gaskets and valve cover gaskets ordered from Pace


Already had:
L67 heads
L67 LIM
L67 supercharger belt drive pullies
L67 Coil pack bracket
M90
L67 Throttle body
L67 map sensor
Coolant
Oil
Oil filter
Copper RTV (for Lim corners, and other sealing)

Originally Posted by 02BlueGT

As title states, i've got some questions before i actually do the work, I took an entire week off of work, but I hope to finish in 1-2 days, anyways on with the questions:

1. I bought head studs, how tight into the block do I screw the studs, and what should I torque the nuts to

2. I bought a HP tuners and plan on running the L36 in injectors for now(so I can get it up and running before I start cutting and splicing fuel injector wires) Is this ok?

3. What should I set the base timing to in my GT pcm, or should I just flash an entire GTP bin and start from there???

4.Should I coat the head gaskets with anything before assembly?

5. The top swap setup I bought only had bolts for the belt pullyes, are the UIM bolts on a L36 the same as the stock supercharger bolts on a L67

6. Does anyone have a good picture/diagram of the L67 vacuum routing?

7. An tips or suggestions before I start?

Thanks in advance for any answers

1. put the studs in hand tight into the block and i believe the package says the torque ratings, which is like 75 ft-lbs. i put mine to 90.

2. you dont have to cut injector wires to run the l67s? they swapped right over with mine.

3. flash the gtp bin, it will work fine. keep your tranny file how it is though.

4. if youre using felpros, leave 'em dry. multi-layer metal gaskets need copper spray.

5. supercharger bolts are not the same as the uim, you need a set

6. map > lim nipple > fpr (leave the bbv open, this will allow full boost)

7. take your time, organize things, dont lose anything. make sure you have oil pressure before you start back up. dont screw up the threads for the crank bolt. make sure it is timed correctly. torque everything properly, be very meticulous.

overall..dont screw it up.

Originally Posted by Bio248

be very meticulous.

Not to discount all the other info you provided, but to me this is by far the best advice. I have avoided countless issues by heeding this advice. I am VERY anal about labeling everything unless I am just absolutely 110% certain I will remember where it goes or what it went to. Otherwise I'll go through a ton of zip loc bags, tags and whatever else I need to in order to ensure if nothing else I can put everything back to the way it was when I started.

I find few people like this and most people that have me service their vehicles, even for relatively simple things expect to come over, get in and get out. But I explain to them, however long you think it will take, multiply that by about 2.5 and you'll have an idea of how long the work will take with me. And I am very clear about why and if they have a problem with that, then I give them the opportunity to either reschedule when it would be okay or have someone else do the work.

If I absolutely know its and easy job that wont require a lot (for instance changing the oil, tune up stuff and so on) then I'll work through it as fast as I can, but if its involved I try and give fair warning.

My boss recently came over with his Bonneville to replace an axle. Simple enough job and thanks to Chris (webracin) Ive gotten to the point where I have one pulled and replaced in about an hour. But I told my boss to plan on at least two for the simple fact I wanted to make sure everything was done right and to have the time to inspect other things while I was in there.

I got the work done in just a tick over two hours. More so because I had some issues getting the strut bolts loose and out, and then because the bonneville is a little different from the GP and I had a hard time finding any leverage to pop out the shaft.

So do be meticulous as it WILL pay off in the end. The first good move you made was taking the time off from work. Utilize that time, dont be in a big hurry. Take a day or two to get the work done. Check, double check and re-check everything, no matter how simple or how familiar you think you are with the process or part. Pay attention closely to torque specs. Use thread sealant everywhere its called for. If you have a digital camera, make much use of it. Not necessarily for a how to or anything but just to have some visual documentation of where things are, where they went to, what they looked like, etc.

Good luck with it all and be sure to let us know how it all goes.

expect this to take you a week if you want it done slow and right. it took me like 3 days, but when i put it back together it wasnt right so i had to go back down into the motor.

after all that i did, it cost me a shortblock due to my rushing and not making sure everything was correct.

^^^Thanks for all the advise everyone, does any one have a good picture or few of the front of an L67 so I can get the pulleys in the right places.....and of the vacuum lines....

And where can I get bolts for the supercharger??

Ok, top swap was a success, but there are a few things left for me to do:

Swap the Harmonic Balance(waiting on james to have a free day, since he has the puller and impact)
Wire in the BBV
Re do the vacumm lines and try to find my leak

So my only real question is; where do the wires for the boost bypass valve go, the brown wire has a pcm pin on it, I just don't know which connector and slot it goes into. and the other wire is either power or ground?

Edit: It is a 2002

forget the bbv wiring. just leave the bottom nipple open to the atmosphere and it will work just fine. your gt pcm cant control the bbv no matter what bin you put on it anyway. youd have to get a gtp pcm for it to work, and there is really no reason to do that.

^^^You sure, cause I thought all PCM's 99+ are the same

well, i cant say for sure on that, but i know when i did mine i couldnt get the bbv to be computer controlled either way i did it. just take the easy way out and leave it unhooked.

I don't know exactly when they became the same, but the part number for my 04 L36 PCM is the exact same as a 04 L67 PCM. No physical difference.

from 1997,the computer is the same part number for l36 gt to the l67 gtp,just needs reprogramming

you cannot program a gt pcm with a gtp bin and have the bbv work correctly. you just cant.

Originally Posted by Bio248

you cannot program a gt pcm with a gtp bin and have the bbv work correctly. you just cant.

The PCM I have in my car is from an L67 and I sent my old L36 PCM to the guy I got it from (we were having to play musical PCMs). He loaded his L67 bin back on my old PCM and his BBV works correctly.

I would say it's year dependent, but it can be and has been done. At some point the part numbers became the same.

i am a partsman at a chevy dealership and im comfirming that the part number is the same for the gt and gtp,they are unprogrammed and you have to put whatever VIN number your using into to input the info,if your using a used unit,the old info has to be wiped out and the new vin info installed

meh..my pcm has nothing to do with what my car is anymore besides the tranny file, hah.

i just have mine open and it works just fine. i dont know if i need a cap or not, never noticed anything weird.

i do know that my car makes a hissing sound that i havent heard other's do when i start to boost, but i like it and it doesnt seem to be running any different than it should so im going to leave it for the time being.

i definately dont have a vacuum leak, if that's what you were getting at.