I bought this really nice K5 but it fell over on the PO's trailer and dinged the fins. There are two different metals used on these heads, the very early heads are similar to the newer ones being a softer and more bendable material. The later K0 through K2 are more brittle, you can identify them by feeling the bottom of the head, if the dowels stick through they are brittle, if they are smooth they will bend more without breaking. This one is more than half done in the first picture.
I used a heat gun on a ladder step to warm up things since the engine was garage cold.
I just worked back and forth from side to side, tightened slowly and kept flattening it out. I wish I'd taken a good before pic, one fin was touching the one above it. I have two of these vise grip folders, this one is bigger and only fits between the fins when you get them close to flat. I carefully used a brass drift and small hammer to fine tune them too, then a single cut flat file. Some sanding and scotchbrite will finish it up.
