Ordered My Longtubes...Prepping for the install
1. Headers and ORY pipe
2. Prothane motor mounts: http://www.jegs.com/i/Prothane/311/7-512-BL/10002/-1
3. Does everyone re-use the stock manifold gaskets?
4. Do most people reuse the stock exhaust manifold bolts?
5. Should i buy o2 extensionsz: http://cgi.ebay.com/ebaymotors/OBX-G...Q5fAccessories
or just for out the $70 a piece for the corvette rear o2 sensors
6. Anyone know how many/what size band clamps i should buy for this install? Something like this right>http://www.jegs.com/i/JEGS/555/30733/10002/-1
Anything else?
Do all of you guys put these guys in from the bottom? Thanks
Last edited by MTBSully; Jul 12, 2010 at 08:13 AM.
You may also need to BFH mod the y pipe where it bumps.
Oh and add Beer, you are gonna need it lol
7. Beer www.Shiner.com
1. Headers and ORY pipe
2. Prothane motor mounts: http://www.jegs.com/i/Prothane/311/7-512-BL/10002/-1
3. Does everyone re-use the stock manifold gaskets?
4. Do most people reuse the stock exhaust manifold bolts?
5. Should i buy o2 extensionsz: http://cgi.ebay.com/ebaymotors/OBX-G...Q5fAccessories
or just for out the $70 a piece for the corvette rear o2 sensors
6. Anyone know how many/what size band clamps i should buy for this install? Something like this right>http://www.jegs.com/i/JEGS/555/30733/10002/-1
Anything else?
Do all of you guys put these guys in from the bottom? Thanks
2. Absolutely! Yes! You'll want to upgrade your motor mounts while you have the exhuast off the car and outta the way. Very, VERY smart decision.
3. I used a new set of GM Gaskets when I did my LT Install, but I wouldn't have needed to. The originals were fine, but I figured since I had bought them and the exhaust is off, I might as well put them to use. We did reuse the originals on my Bro's 02 SS when we installed his LT's, but his car has like 4500 miles on it. So they were in like new condition.
4. Every LT install I've been a part of (3 Total) we've reused the stock manifold bolts without a problem. Alot of guys use Anti-Seize on the threads, I used medium strength Thread Locker to be sure the bolts wouldn't back out over time.
5. O2 Extensions are the cheaper way to go, rather than purchasing the Corvette O2's. (Thats the method I chose.) Unless you know which pins to swap in the PCM. Inwhich case you can use the rear O2 Sensor harnesses for the front O2 Sensors and then you wouldn't need to buy either one. I'm not exactly sure how this is done, so if you're interested you'll probably wanna do a search.
6. Depending on the number of pieces your Y-pipe consists of, you'll need a 3" clamp for each connection (and don't forget one for each connection to the collectors on the headers) and a 2 3/4" Band Clamp for the Y-pipe to Catback connection. The ones in your link look nice, but I used different ones on the installs I was a part of. (PM me if you'd like to know where I found mine.)
And lastly... Yes. Every Longtube Header Installation must be done from under the car. Unless, of course, you have the drivetrain removed from the car. And in this case you can install them from any direction you like.

Good luck, man.
List looks good other than that.
If it was me, I would buy the extensions b/c sometimes the fumes and **** burning off of new headers will kill the 02's anyway. So spending $70 on a new set and if the header kills them, that would blow.
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http://chevythunder.com/1999-2002%20...%20pinouts.htm
Take the 1 screw out of the blue connector, then use a small screwdriver to pop the grey cover off of it, and to pop the blue parts off as well, the releases for the grey cover are obvious when you look at it, you do NOT need to take the screw out of the connector to get the grey cover off, (you need to snip the small zip ties and re-do them later) and the blue pieces are held on by tabs on the ends...just put the ends in slightly (where white sticks through them) and they come right off...the pins then pull out towards the wire side when you pull the white lock tabs ever so slightly away from them. In that blue connector, swap the following pins:
25 swaps with 26
28 swaps with 29
65 swaps with 66
68 swaps with 69
Thats IT...put the blue pieces back on, put the grey cover back on, replace those small zip ties, make sure the orange gasket is seated properly to keep water out of there, and bolt the connector back onto the PCM. Plug your front O2's in to the REAR connectors under your car...get brand new stock O2 sensors for your car and plug them right in.
THE HARDEST part of the pin swap, is getting the grey cover off of the PCM connector...and with a small screwdriver or pick, that is a fairly easy task. Northern cars/trucks tend to show a little more corrossion on the metal body of the plug which makes it harder to get the cover off...but with patience (and 3 minutes) it comes off.
Those headers are race style right? If so have the AIR system removed since you can't hook it up anyways to the headers, and remove the EGR too, if 2000s have that (don't remember).
And if those headers are stainless, I'd buy a set of stainless header bolts to compliment it and never worry about rusty bolts. I bought a set for $18 shipped from Summit.
I also bought a pair of new GM exhaust gaskets from Tick for $35. Since they didn't come in yet, today I called a GM dealer a couple miles down the road and asked what they charge for the gaskets. $15 a piece. Doh! I would have saved a little money and had them faster, but since he had to order them in, I didn't bother and will just wait for the gaskets I already ordered to come.
http://chevythunder.com/1999-2002%20...%20pinouts.htm
Take the 1 screw out of the blue connector, then use a small screwdriver to pop the grey cover off of it, and to pop the blue parts off as well, the releases for the grey cover are obvious when you look at it, you do NOT need to take the screw out of the connector to get the grey cover off, (you need to snip the small zip ties and re-do them later) and the blue pieces are held on by tabs on the ends...just put the ends in slightly (where white sticks through them) and they come right off...the pins then pull out towards the wire side when you pull the white lock tabs ever so slightly away from them. In that blue connector, swap the following pins:
25 swaps with 26
28 swaps with 29
65 swaps with 66
68 swaps with 69
Thats IT...put the blue pieces back on, put the grey cover back on, replace those small zip ties, make sure the orange gasket is seated properly to keep water out of there, and bolt the connector back onto the PCM. Plug your front O2's in to the REAR connectors under your car...get brand new stock O2 sensors for your car and plug them right in.
THE HARDEST part of the pin swap, is getting the grey cover off of the PCM connector...and with a small screwdriver or pick, that is a fairly easy task. Northern cars/trucks tend to show a little more corrossion on the metal body of the plug which makes it harder to get the cover off...but with patience (and 3 minutes) it comes off.
Thanks for posting up!







