Harmonic balancer??

We had the same thing with our 273 cover on 340 block and with a new Pioneer harmonic balancer: cover marks are on the passenger side but the mark on the damper is over on the driver's side at TDC.

2 solutions:
- Make a timing marker for the driver's side to mate up with your mark on the damper.
- Make new marks on the damper to line up with the ones on the 273 cover.

Here is a pix of our added timing indicator on the driver's side, made from 1"X1/8" steel strap. The long flat part presses hard against the side of the timing cover to keep it very stable.

A timing tape on the damper is a very nice addition with either solution. We added a Mr Gasket timing tape afterwards to the damper and measure timing against the 0 mark on the new scale. Note that the Pioneer damper pictured here is quite not the same diameter as the stock SBM damper so a 7" BB Chevy timing tape actually gives a bit better accuracy with that damper, but either is around 1 degree off at 45 degrees advance so either is reasonably accurate.