Hello Mate!
In my experience, engines are much easier to fix than all that welding/painting/plastic stuff. I'd always go for a good looker and fix up the engine if required. If your chop is a 550, can you tell us what it was based on? I see you're in the UK so it was either a 75/76 F or a 77/78 K?
Jim Shea (Camberley) runs an informal UK mailing list. Interested?
Where are you? (fill in your bio!)
Then post some pictures in the gallery.
Steve in Wokingham
PS - not trying to be a pedant (much) but please try to write in sentences as it makes it sooo much easier to read
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and... why "boggy"?