Larry,
Look up Bolt torque on google.
There's lots of good charts.
I just made the sameinquiry for my 1930 DeSoto Model CF 8 Cylinder.
3/8 X24 Rod Bolts assuming grade 5.
Plain bolt torque is 35 ft. lbs.
I think that your 40 ft. lbs. is right in the ball park!
_________________________
Steve Boettger
Iroquois Region President
'30 DeSoto 8
'59 Nash Metropolitan
'23 Chevrolet Touring