mike,
Thought I'd responded to this (but I must've hit the "back" button instead) and provided some information. The F-head weighs about 470 lbs. from here:
https://cj3b.info/Hurricane.htmlBut that's with everything. Then I was looking up info on the airbreather hose and found KW sells those new blocks, Allied I think. The block should be pretty much the same for either F or L head and on their link for that block a question was asked how much it weighs:
https://www.kaiserwillys.com/new-4-cylinder-engine-bare-block-fits-41-53-jeep-willys-with-4-134-l-engineKW's answer was about 88 lbs. (I wonder if that was supposed to be 188lbs).