my machine motor #is9U2776 what would identify it a 315 or 333 also what is the manufacture date thanks jw45

All the D6 8U's and 9U's used the D318 engine.
Yours is 1949 production.

OM is right it is a D318 engine and is a 6 cyl. version of the D315 a 4 cyl. The D333 is a 6 cyl. engine and followed (replaced) the D318 but was a completely new and different engine and the only similarity is the bore and stroke are the same but that,s all.

is the headbolt torque sequence on 318 the same as 311 what is the hp rating of this engine

No, not the same as the D311, but similar technique.

The only difference with torquing heads on these engines from most others is the row of studs down the center take a different torque and are not part of the tightening sequence of the other fasteners.

Look at Willie's CAT page for the torque and pattern. Click on the thumbnail picture and it will open full sized so you can print it off.
www.westernfarmcollectables.com/specs.html

Your tractor is rated 66 drawbar hp and approximately 75 belt hp ( can't find that spec right now) and governed at @ 1550 high idle rpm. Later models of the 8/9U after 1953 were a little higher at 75/85 and governed @1750 rpm.