im rebuilding my 355 2 bolt, just put all new bearings in but when I torque the connecting rod bolts down to 40lbs I cant spin the crank... when I loosin the bolts on the connecting rod I can grab the flywheel and spin it easy but when I torque them it just feels like its seezed.. any ideas?

 

Look at your caps again. Make sure they line up correctly. Tang to tang. Beveled side of top cap faces the closesest counterweight on the crank. Look at your pistons after youve popped them in. Make sure the dot on the piston faces the front of the engine.. If it aint these. Run your finger around the journals . See if you can catch a bad scratch. And if it aint that. You might need new sized bearings

 

You may also have rods in backwards.

The rod bearings don't sit in the center of the rod; they're off to one side a bit. This is to clear the radius at the end of the rod journal. If they're backwards, the bearing will be on that radius, and it will lock the motor up solid.

Easy enough to tell: one side of the big end of the rod has the tangs. That side should face away from the cam tunnel (toward the oil pan) on all 8 rods.