My question regards the "bearing insert piece" that i believe to go in the center of the camshaft gear. Is this correct and what exactly does this piece do? BTW, this is in a 400 SBC that im rebuilding in my '72. Thanks

its a thrust button. it is for gear drives and roller cams, a regular flat tappet cam [95%of all cams used in chevys] it is not mandatory.

it keeps the cam from walking out the front of the motor, grinding thought the timing cover.

thank you, i appreciate the input.