if you are turning it over with the head back on or already on and your spark plugs in, then yes it is a bitch to turn over, take them out and then try.
also if i am remembering correctly, you should lube each bearing after you put in it it's place, then bolt the cap on.
did you also check to make sure that the rod bearing didn't spin when you rotated to put the other two in?
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if you can only race me in a straight line then whats the point 
...91 SMF SCCA
http://www.flickr.com/photos/8341770@N07/5601083432/http://www.flickr.com/photos/8341770@N07/5601083432/ by http://www.flickr.com/people/8341770@N07/, on Flickr
I see people out there spending money on the car to improve it … If you spend half that effort just working on your driving skills, making you and the car work together as a team, then you’ll go faster – period. To make the car go a second faster on the track takes a lot more energy and money than making yourself drive it one second faster.
– the late Tom Thrash SCCA Solo E Production