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Thorley Headers, please help

chev4life

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Jun 21, 2001
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San Jose, CA
I just installed my throley headers last night and the ypipe at the collector is hitting (not quite about a paper sheet above) the frame rail. Has anyone had this problem...if so how to fix? I have thoguht about adding a small wedge or even a second gasket between the header the ypipe flange and try to angle it up...just havent had a chance to try it. Any help would be great, want to get this cured this weekend so I can get the collector flange welded to my cat. Thanks.
 
Are you sure you got the right ones? When I had my thorley small block headers they just dropped right in, no clearance issues, my big blocks were a little more work, But as I recall my smallblocks were nowhere near the frame. I have however heard of people getting sent the wrong style, check your numbers.
 
They are the right ones, everything lines up real nice...except it is close in one location...but it dumps almost dead straight wiht my stock cat. I am thinking the slight angle decreace from lowering my t-case with the stock "spacers" might be the problem. Just need some ideas on fixing, cause I dont want to cut or bend my frame.
 
i had the same problem on my 89'. it is on the driver side right? i too have the tranny case dropped and i think thats the problem.

what i did was just take a large adjustable wrench and bend the lip of the framerail down a 1/4 inch or so right where it hits. you dont have to bend it much.just enough to get you about an 1/8 inch clearance. it wont weaken the frame at all.

its either that or raise the T-case back up and run a CV joint.dont cut it tho.
 
What I did to clear a header one time was to take a die grinder, with a carbon wheel blade, and make two one inch cuts in the frame. I then took a long steel punch and hammer, and bent the small tab I created in the frame down.
 
So guys went the frame way...I am beginning to think that is the only way to do it without bending the headers. I will try the pry session first then hit up the grinder if need be. I am also gonna try to double up the gaskets on the drvr side to get a touch more length, it might lift it a touch also...but will see in the morning when I slide under the beast again. Thanks for the help guys. /forums/images/graemlins/grind.gif /forums/images/graemlins/hack.gif /forums/images/graemlins/k5.gif
 
i dont think youll need to cut it. i wouldnt bother with gaskets either. all you need is enough clearance so it doesnt rub under motor flex. 1/4" should be fine.
 
All fixed. I pulled out the trusty wrench and bent down the lip of the frame, have a good 3/8" between now /forums/images/graemlins/waytogo.gif Got the exhaust hooked up to it and everything is nice /forums/images/graemlins/peace.gif, thanks for the help guys /forums/images/graemlins/bow.gif
 
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