I have an 81 sa 200 a 67 red face sa 200 and an 04 300d. The 81's block cracked this winter but the frame, doors hood etc are mint. the 67 was running when I stored it but needs a total restoration to be reliable doing the 7 days a week 12 hours a day thing. The 300d is a good all around machine but I've never been 100% satisfied on how it pipelines(yeah I've done the roll the brushes and tamper with the ocv and rpms). I spoke to a salesman the other day and he said the difference of trading my 300 on a 200d was X amount. I spoke to the guy that does all my sa 200 work and he said to rebuild my 67 f 162 (already has a 163 head so I can put my electronic ignition on it) take the engine and barrel out of my 81 and swap the all the 67 stuff into the good frame, it would be roughly the same amount of $$$. 
So... brand new 07 200d or brand new 67 red face? fuel economy is crap with the 67 but it's a 67! help!!