Hey Stephen
You can do what I did and take it for a drive - then you can find all the things that come loose.
Just strap your engine and transmission onto your frame, hook up some rope to steer and away you go.
Make sure that you have plenty of room to stop if you dont have brakes fitted or wear some thick sole shoes to apply manual pressure to the tyre.
I did this with mine and found lots of things to tighten (although I do confess that I went for a delux version with the steering wheel
video example available here:
http://members.optusnet.com.au/lobelly/
But seriously, put the engine in your chassis and get it going there - a lot of the build centres around the engine and getting things to work with the engine in-situ.
have fun
LoBelly