wanting to swap a few 6.1 parts onto my 5.7

If the crank from the 6.1 is not damaged I would definitely use it in place of the 5.7 crank. The 6.1 crank is forged and is the same stroke as the 5.7. If at all possible, I would also change to a forge rod and piston. Now you have a complete forged bottom end to build on. That is what they did with this build: Swap a 6.1L Crank Into a 5.7L Hemi For 440 HP