My newest purchase...

yes- it's usually worse
that motor might just outrun his 340
re-lube the cam and rockers/ tips etc take a peek at the retainer clearance just in case
you can use some thinner head gaskets if you want to
double check the cam timing- often cams just put in on the marks easy to do on the engine stand
check all the little things like drilled galley plugs behind the cam sprocket
double check the retainer clearance
looks good
post up your cranking compression when you get it together
watch out for shop rag or scotchbright crap and check a couple of bearings for scratches
I doubt if it was put together dirty but you never know