I have read that you need a different crossmember for a 4L80 swap. Why do you need a different one, how far is it off, and can't you just flip the crossmember? I'm ordering one regardless but just want to make sure I am right. So I can tell someone who am right.

 

The transmission mount sits further back, the stock crossmember is just straight so flipping it around puts it in the same spot.

You can cut and weld on extension pieces on the side to make it longer or just buy one already made.

Or you can take the stock cross member, make a plate and weld it to the side to make the top bolt section another 2-3in longer. Then make a triangle piece on both sides to make it solid. Measure your holes, drill them and you are done.

 

Good thing I am but a new crossmember.