LS3 swap headers for 59
 

I know i saw it previously in my searches, but can anyone confirm that the 73-87 long tube swap headers fit well enough to use?
Thanks

Re: LS3 swap headers for 59
 

Why yes Bill the Speed engineering long tube are great with plenty of room

Re: LS3 swap headers for 59
 

lol, talking to yourself is the first sign.......
sorry, busy last night and didn't get to the computer. I used camaro manifolds in the original frame so I couldn't answer your question anyway.
looks like you got started anyway.
you may want to check the frame for straight, square and sag before welding anything in place. for straight chack an easy way id to mark each cross member at it's mid point between the rails, then run a string or laser down the middle to see if they all line up. for square do a corner to corner check, for sag do another string test on the top or bottom of each rail, use a measured block between the string and the rail on each end, then use another block, or simply measure the gap, to check along the length to ensure the gap is uniformly the same as you go along.