Sounds about right, might even be loose unless your screwdriver is really long.
I measured the torque on the last 270 that I put together while installing an NOS rope seal from a military surplus kit and it went from spinning freely by hand to between 15-20 ft lbs to spin the crank. I sequence torqued the main caps to 100 ft lbs.
I packed the seal in till it was squeezing over the groove edges and beat it into shape with a large socket and rubber dead blow mallet before installing the crank. Then a dab of RTV on the ends of the packing when doing final assembly.
I have over 1000 miles on it now and rear seal is as dry as can be.
