Need help timing a 350 TBI chevy?

You should have both marks at the 12 oclock position. The timing cover and the harmonic balancer may not go together. There are several versions made. If they came off the same engine then of course they do go together. Some Chevys have the timing adjusted to help the engine produce lower emissions by placement of the keyway in the "wrong" position on the timing sets. The only way I know of to be sure of what is going on is to set number 1 at TDC and see where your marks are. The timing gear marks should both be at 12 oclock and of course you want your 0degree mark on your balancer lined up with the pointer on the timing cover.