Ok if I wanted to swap engines. How much can I buy just the engines for, installation not included.

What about the
SRT4
SRT6 (currently in the crossfire SRT6)
SRT8
SRT10
LS1 (i have seen some of you hear mention)

Can anyone find or know the prices these engines sale for by themselves. I would love to estimate the total costs of just buying all the parts if I wanted to do a swap.

Thank you for your time and assistance