They want your head for the parts mostly - to rebuild the new heads. If you don't want to give up your head - look around on Craigslist for a SOHC that's being parted out. I found one when I needed because I didn't want to give up my original head either.
I worked out a deal, sent them the 'return shipping' box and some $$ for their time to send their head back for me.
Member of the Dropped Valve Seat Club.
Replaced #4 Piston, Rings, Rod+Bearings, AERA Re-Manufactured Cylinder Head and a light Hone. Then CLEANED the hell out of everything.