Safe maximum HP and Torque for Drivetrain

[1971gophercatcher]

My project is a 1971 C-10 Cheyenne Super

I need some expert guidance here. My goal is to upgrade to a new engine and keep my stock TH 350 transmission and stock 3.07 non Posi 12 bolt rearend.

What is the safe maximum amount of Horserpower and torque that my stock drivetrain can handle? I would like to stay between 300 and 400 for HP and torque if I can.

Please share where I can find this kind of information. I’ve been all over this forum and internet with no luck.

Thanks in advance!