MAV
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There are several how-to threads, videos, etc. out there, and there's a few threads with bullet points. This is another one of those specific to the GT350 and Kooks headers. Header brand will change some of the minor points, so keep that in mind (i.e. I've read that the starter won't go back in without removing the solenoid, but I had no problem getting it in through the Kooks header design).
I've installed lots of headers on lots of cars in my life. This job was more difficult than any of them by a factor of ten. It's insane how hard it is to get to every bolt to remove the factory headers, and it's only worse when you're trying to get to them when installing the new ones. They are larger, with longer tubes, and you can't use the factory studs in all places. I will say, however, that if you take your time and look, you can usually figure out a way to get a socket on several of them, but it does take time and creativity. That's the damnable misery of all the how-to videos out there...NOBODY details how to get to the bolts. Everyone says, "There are no tips and tricks, you just have to be creative." Unfortunately, that's not a cop out. It's pretty much true.
1. First and foremost, get proper tools. You MUST have a collection of wobble sockets and/or adapters. You MUST have flex-head ratcheting wrenches. You MUST have several lengths of 3/8 and 1/2 extensions. It's NICE to have air or power tools (and I would add that without an air ratchet, I'm not sure I could have gotten some of the factory bolts off - just no room in there to ratchet a socket or wrench).
2. I have a lift in my shop. I personally could not have done this job without it, but I'm older and fatter than a lot of you, so that's not an absolute necessity. I would shudder to think about doing it on jackstands, but that's up to you and the facilities you have.
3. Everybody says the passenger side is the hardest. I would say that's true, but don't let that fool you into thinking the driver's side is easy. I think most people say the left side is easier because they've already done the right side and learned a thing or two in the process. I'm not sure if it's better to start right or left, but you will learn some things in the process, so keep that in mind.
4. The dreaded passenger side front bolt: I didn't find it to be as difficult as most. Again, with the proper tools - i.e. 15mm flex-head ratcheting wrench, I was able to get my left hand contorted around the A/C lines to get the head on the nut, hold the head to the nut with my thumb while I used my remaining fingers to operate the wrench. It's not easy, but it wasn't as difficult as I was expecting.
5. With the proper flex sockets/adapters and extensions, I was able to get to most of the rest of the passenger side bolts from underneath once I removed the starter and motor mount bracket. Don't use your impact or other power tool to break bolts lose. Figure out a way to get a socket or wrench on a bolt/nut and just get it moving with leverage from a breaker bar or similar. Once loose, then use your power tools to finish removing. Sometimes the joints in the flex adapters are strained too much for power tool use until the fastener is broken lose.
6. I removed the battery cable but not the battery and box. I did not remove the airbox, but I still have one bolt to go on that side (one of the top middle bolts), and I may have to ultimately remove it to get enough room to get my arm in the right place for that bolt. I'll update the post if I have to do that. I removed the actual motor mount on the passenger's side because I read that you should, but I don't think it was necessary. I did not remove it on the driver's side, and I didn't have a problem getting the headers in. I also did not remove the fasteners on the steering column at the firewall. I had no problem removing the steering knuckle without this. Be sure to mark everything so it goes back together the same way you took it apart.
7. Again, specific to Kooks with their slotted mounting flanges, I was able to utilize all four of the upper studs on the passenger side and the front three on the driver's side. There was sufficient clearance between those studs and the tubes to get a nut and wrench/socket on the studs to tighten them. I used four Stage 8 locking bolts on the bottom. Wasn't able to get the C-clips on the locking tabs on the front two passenger side bolts, so I installed the tabs, and dabbed a bit of RTV on it to hold it in place. Not sure if this will last long term, but my thinking is that even if the bolt tries to back out, there's no pressure on the tab to try to come off the bolt. It's just trying to keep it from turning. We'll see. No worries if they fall off, because those two bolts are easy to access with extensions and a flex socket from the wheel well.
8. When installing the passenger side header, WORK THE MOTOR MOUNT BRACKET IN WITH THE HEADER!!! It WILL NOT fit once the headers are hung on the studs/bolts, even if they are loose because the transmission cooler lines are in the way. It's easy to work it in when you're lifting the header into place, and it can just sit there while you work on tightening bolts/studs. I read somewhere not to tighten the header completely until the motor mount was reinstalled, but I think I could have gotten the locking tabs on the front two lower bolts if I had done it before I tightened up the motor mount. The starter needs to go in at this time, too. Everybody complains about the top bolt on the starter, but it's not that bad with some creative wrenching and socket extensions.
9. As for motor mounts and jacking the engine up...GT350s have the composite pan, so you'll have to get your jack on the edge of the bellhousing for support and moving up/down. I guess it's okay to have both motor mounts disconnected when jacking, but I did mine one side at a time. That way, when I jacked the motor (or released it to move it down), all the movement was limited to just the side I was working on. This probably doesn't matter, but I thought I'd include it. As everyone else says, be careful with what you're hitting on the firewall at the top of the engine. I was able to get everything done with minimal jacking.
10. For any bolt holes where studs are removed, chase them with a tap. Be careful...you DO NOT want to cross tap or cross thread these holes. That's an expensive mistake. The header bolts are exponentially easier to start and turn with your fingers once you've cleaned out these bolt holes. Another tip - use the same tap to chase the threads of any of the stud nuts you are reusing. Those nuts are side-pressed, meaning the threads are tight all the way up and down the stud. If you chase them with a tap, you cut out the part of the threads that make it tight, and it's now just a regular nut. MUCH easier to spin those on the studs with your fingers than to spend 30 minutes on each one trying to get it to spin down tight with a wrench that won't fit into the space anyway. If you're worried about them coming loose, then just double-nut them. I did a few of the easier to access ones, and I'm leaving a few of the harder ones, so we'll see if they loosen up.
11. If you're using the Stage 8 bolts, don't forget they have an Allen wrench fitting in the center that can make it easier to snug up in tight spots. Don't try to use them for final tightening though...the tool is too small, and you'll break it off in the bolt head.
12. I'm finishing up the driver's side (still have that one nut to go on the top center pair). I will say that reinstalling the driver's side has been the hardest part of the whole job. The top rear bolt is impossible to get to with anything other than a wrench from the bottom of the car. I STILL don't know how I'm going to get that last nut on. But other than that, they are done. I've got all the connections back together, motor mounts and starter tight, checked clearances, and all seems to be good. I have read other threads that discuss issues with clearances and other things, and I'm glad I went with Kooks. No issues at all in that department.
I've got the Kooks Green Cat midpipe, and I've bought some resonators to install in the midpipes before they connect to the factory axle backs. I didn't want the stink, I didn't want the rasp, and I didn't want to lose my selectable exhaust. I'll probably tune for E85 at some point, but may wait until the factory powertrain warranty is gone just in case. Hopefully I won't run into a CEL issue with the green cats.
I hope this helps somebody searching the Interwebs for header install issues!
I've installed lots of headers on lots of cars in my life. This job was more difficult than any of them by a factor of ten. It's insane how hard it is to get to every bolt to remove the factory headers, and it's only worse when you're trying to get to them when installing the new ones. They are larger, with longer tubes, and you can't use the factory studs in all places. I will say, however, that if you take your time and look, you can usually figure out a way to get a socket on several of them, but it does take time and creativity. That's the damnable misery of all the how-to videos out there...NOBODY details how to get to the bolts. Everyone says, "There are no tips and tricks, you just have to be creative." Unfortunately, that's not a cop out. It's pretty much true.
1. First and foremost, get proper tools. You MUST have a collection of wobble sockets and/or adapters. You MUST have flex-head ratcheting wrenches. You MUST have several lengths of 3/8 and 1/2 extensions. It's NICE to have air or power tools (and I would add that without an air ratchet, I'm not sure I could have gotten some of the factory bolts off - just no room in there to ratchet a socket or wrench).
2. I have a lift in my shop. I personally could not have done this job without it, but I'm older and fatter than a lot of you, so that's not an absolute necessity. I would shudder to think about doing it on jackstands, but that's up to you and the facilities you have.
3. Everybody says the passenger side is the hardest. I would say that's true, but don't let that fool you into thinking the driver's side is easy. I think most people say the left side is easier because they've already done the right side and learned a thing or two in the process. I'm not sure if it's better to start right or left, but you will learn some things in the process, so keep that in mind.
4. The dreaded passenger side front bolt: I didn't find it to be as difficult as most. Again, with the proper tools - i.e. 15mm flex-head ratcheting wrench, I was able to get my left hand contorted around the A/C lines to get the head on the nut, hold the head to the nut with my thumb while I used my remaining fingers to operate the wrench. It's not easy, but it wasn't as difficult as I was expecting.
5. With the proper flex sockets/adapters and extensions, I was able to get to most of the rest of the passenger side bolts from underneath once I removed the starter and motor mount bracket. Don't use your impact or other power tool to break bolts lose. Figure out a way to get a socket or wrench on a bolt/nut and just get it moving with leverage from a breaker bar or similar. Once loose, then use your power tools to finish removing. Sometimes the joints in the flex adapters are strained too much for power tool use until the fastener is broken lose.
6. I removed the battery cable but not the battery and box. I did not remove the airbox, but I still have one bolt to go on that side (one of the top middle bolts), and I may have to ultimately remove it to get enough room to get my arm in the right place for that bolt. I'll update the post if I have to do that. I removed the actual motor mount on the passenger's side because I read that you should, but I don't think it was necessary. I did not remove it on the driver's side, and I didn't have a problem getting the headers in. I also did not remove the fasteners on the steering column at the firewall. I had no problem removing the steering knuckle without this. Be sure to mark everything so it goes back together the same way you took it apart.
7. Again, specific to Kooks with their slotted mounting flanges, I was able to utilize all four of the upper studs on the passenger side and the front three on the driver's side. There was sufficient clearance between those studs and the tubes to get a nut and wrench/socket on the studs to tighten them. I used four Stage 8 locking bolts on the bottom. Wasn't able to get the C-clips on the locking tabs on the front two passenger side bolts, so I installed the tabs, and dabbed a bit of RTV on it to hold it in place. Not sure if this will last long term, but my thinking is that even if the bolt tries to back out, there's no pressure on the tab to try to come off the bolt. It's just trying to keep it from turning. We'll see. No worries if they fall off, because those two bolts are easy to access with extensions and a flex socket from the wheel well.
8. When installing the passenger side header, WORK THE MOTOR MOUNT BRACKET IN WITH THE HEADER!!! It WILL NOT fit once the headers are hung on the studs/bolts, even if they are loose because the transmission cooler lines are in the way. It's easy to work it in when you're lifting the header into place, and it can just sit there while you work on tightening bolts/studs. I read somewhere not to tighten the header completely until the motor mount was reinstalled, but I think I could have gotten the locking tabs on the front two lower bolts if I had done it before I tightened up the motor mount. The starter needs to go in at this time, too. Everybody complains about the top bolt on the starter, but it's not that bad with some creative wrenching and socket extensions.
9. As for motor mounts and jacking the engine up...GT350s have the composite pan, so you'll have to get your jack on the edge of the bellhousing for support and moving up/down. I guess it's okay to have both motor mounts disconnected when jacking, but I did mine one side at a time. That way, when I jacked the motor (or released it to move it down), all the movement was limited to just the side I was working on. This probably doesn't matter, but I thought I'd include it. As everyone else says, be careful with what you're hitting on the firewall at the top of the engine. I was able to get everything done with minimal jacking.
10. For any bolt holes where studs are removed, chase them with a tap. Be careful...you DO NOT want to cross tap or cross thread these holes. That's an expensive mistake. The header bolts are exponentially easier to start and turn with your fingers once you've cleaned out these bolt holes. Another tip - use the same tap to chase the threads of any of the stud nuts you are reusing. Those nuts are side-pressed, meaning the threads are tight all the way up and down the stud. If you chase them with a tap, you cut out the part of the threads that make it tight, and it's now just a regular nut. MUCH easier to spin those on the studs with your fingers than to spend 30 minutes on each one trying to get it to spin down tight with a wrench that won't fit into the space anyway. If you're worried about them coming loose, then just double-nut them. I did a few of the easier to access ones, and I'm leaving a few of the harder ones, so we'll see if they loosen up.
11. If you're using the Stage 8 bolts, don't forget they have an Allen wrench fitting in the center that can make it easier to snug up in tight spots. Don't try to use them for final tightening though...the tool is too small, and you'll break it off in the bolt head.
12. I'm finishing up the driver's side (still have that one nut to go on the top center pair). I will say that reinstalling the driver's side has been the hardest part of the whole job. The top rear bolt is impossible to get to with anything other than a wrench from the bottom of the car. I STILL don't know how I'm going to get that last nut on. But other than that, they are done. I've got all the connections back together, motor mounts and starter tight, checked clearances, and all seems to be good. I have read other threads that discuss issues with clearances and other things, and I'm glad I went with Kooks. No issues at all in that department.
I've got the Kooks Green Cat midpipe, and I've bought some resonators to install in the midpipes before they connect to the factory axle backs. I didn't want the stink, I didn't want the rasp, and I didn't want to lose my selectable exhaust. I'll probably tune for E85 at some point, but may wait until the factory powertrain warranty is gone just in case. Hopefully I won't run into a CEL issue with the green cats.
I hope this helps somebody searching the Interwebs for header install issues!
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