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Old Apr 21, 2011 | 06:27 PM
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Looking at installing Thorley headers this weekend onto my gxp and I have a few questions. How many people here have installed them themselves vs taking them into a shop to get it done. Also how difficult is the install on a whole, and the weld at the end. my last question is is it better to reuse the factory gasket or replace it with a multilayer bi-metal gasket
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Old Apr 21, 2011 | 06:52 PM
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4-6 hr install. reuse your gaskets and be prepared to get hacked off at reinstalling the trans dipstick tube bolt. the collector will need to be welded to the cat. if your cattless then shops wont touch it.
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Old Apr 21, 2011 | 08:34 PM
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It took me and a friend and 5 hours with a lift to install the headers. And like David said a few bad words
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Old Apr 21, 2011 | 08:41 PM
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O yeah that trans dipstick tube bolt is a MOTHER F#C%ER.
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Old Apr 21, 2011 | 08:53 PM
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took me about 4hrs in a shop with a hoist. i got the motor nice and hot and broke all the bolts loose first and went from there, pretty simple.
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Old Apr 21, 2011 | 09:04 PM
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I just received mine today. What do you have to do to move the tranny dipstick? Anybody got pics? This is the only part of the install that I do not understand.
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Old Apr 21, 2011 | 09:17 PM
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https://ls1tech.com/forums/ls4-perfo...update-62.html
Post#1235
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Old Apr 21, 2011 | 09:49 PM
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Wow, 4-6 hours! Apparently I suck at installing headers. Took me about 12 hours over two days, I just used ramps to lift the car up. The best part was driving the car to get the rest of the exhaust welded on at Fritz's muffler shop in San Marcos TX.

short clip

http://www.youtube.com/watch?v=TSwkhczvsic
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Old Apr 21, 2011 | 10:24 PM
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I had her on all 4 in the air,wasnt that bad of install just time consuming(beer and smoke breaks),open header to the muffler shop put a on my face.Here are a few pics when i did mine(sorry cell phone pics)
http://s678.photobucket.com/albums/v...headers%20LS4/
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Old Apr 21, 2011 | 11:28 PM
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Good thing its a long weekend I have two extra days here to get it to work, and hopefully find some one to weld it up for me.
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Old Apr 22, 2011 | 06:40 AM
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yep took me about 5 hrs. The only thing i did different from what the instructions said if i remember right is it says to slide the rear header in from the top past the valve cover but i found it easier to just slide it in from the bottom. also open headers to the exhaust shop was awesome.
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