has anyone seem or done an ls1 swap intoa c3 i'm looking at a 82 with a blown motor right now, and have a ls1 and auto trans to put in it, any help would be appricated.

I've seen them done in C-1's.  One guy used a crate motor, the other from a wreck.  Both used a wiring harness from Painless.

since this a rather old post ... do you have an update .... i've been considering the LS1 for replacement for the ole cross fire ..... any advise .??

I just brought my motor home this weekend. As you may know these motors share nothing in common with the old small blocks. You will have to come up with some motor mount adaptors. I have a good lead on some of those plus I have some drawings if you want to make your own. You will have to have a fuel pump capable of supplying fuel pressure the motor requires and a fuel return line. There are going to be some computer stuff you will want to eliminate when it comes time to make the motor run. VATS, rear cats, fan turn on off temps etc....
I am going to be gathering stuff to make my swap as easy as possible this summer and jump in after it this fall/winter.
A good place to look for some info is over at www.ls1tech.com there is a hybrid conversion part to the website and some pretty knowledgeable folks in there.

I've recently seen some TV shows installing the LS-364 in some older cars.  It's basically a new LSx engine with a carburetor.

This might help a little: http://matt.undiagnosed.org/ls1/ls1_swap_home.html

[QUOTE=jgoglick]This might help a little: http://matt.undiagnosed.org/ls1/ls1_swap_home.html[/QUOTE]

Great website listed there. His install is nice and clean looking. I am hoping mine turns out to be very tidy also. Should be lots of fun.