hi.
wondering why my engine sounds like a sewing machine (at least to me) and if this has a known cause - so maybe I can fix it, or have it fixed, or not worry about it 
So, I have a 1957 6 cyl engine (in a 1955 3100).
engine starts and runs.
I have not taken it on the road, just around my house.
fairly smooth engine with occasional misfire (I think it is a misfire).
I changed oil, plugs, wires, etc.
if I had to guess, by the looks of it (and I know that is subjective), it has very high mileage.
overall, it is pretty good engine except for two things:
1. smoke - not a lot when idling, but if you really gun the engine out it comes. not like a big cloud of smoke that you can't see through, but enough that you say wow, there is smoke (guess I will live with that for now)
2. sounds like a sewing machine - clickety clackety. not sure if I am describing it correctly, but that is what it sounds like.
it doesn't sound like another 1957 6 cyl engine I have in a different truck. that other truck just sounds like an engine - no clickety clackety noise (or if there is, it is very very subdued).
any ideas what this might be, is it 'normal', and what I could or should do about it, or not do?
thanks in advance
so much to learn....
