Ok I have read several times that people are using BBC headers w/ lsx flanges on them. However I have not been able to find anyone who has actually done it. If there is anyone who has done it could you please post some pics of them and where you cut the tubes in order to get them to line up with the flanges. Thanks.

 

I've done the swap with 351W Ford headers. I took my LS exhaust gaskets to Advance and lined them up over a 351 Ford gasket, a perfect match except for the port shape. IIWY, I'd do the same but with the BBC gaskets. One nice thing about cutting/replacing the flanges, you have a bunch of "wiggle room" for a better alignment. Bolt up the LS flanges, stick the header tubes into the flanges, and push/pull/rotate the tubes until they clear everything. Then tack them in place and do a final check before weld-out.