5W-30 mobil 1 in the motor, redline MT90 in the toploader, Moroso climbing gear in the power lock with two tubes of GM anti slip additive.
As for motor
oil weight, run what the builder recommends or enough vis to get the pressure where you want/need it.
351 cleveland built 'tight' standard pump 30 psi hot idle up about 8-9 psi per thousand pressure relief in about the 90psi range.
Rick