Quick BBC build

[TheKarStop]

Ok guys this is my first , I'm called OG cause of my age but I've come across a BBc build that I had to rush on and now I can't get her to fire! Quick build meaning disassemble and install new bearings, cam, crank, and rods, plus rings, set in a gear drive instead of chain, but my timing mark at TDC doesn"t match any tab on timing cover . This block is a Gen V or VI because of single rear main plus a 6 bolt timing cover made out of plastic. also not sure of harmonic balancer being correct Gen! THe thing is she won't start, any and all advice is greatly accepted!!!! Thank you.....

[Driver50x]

You can use a piston stop that screws into a spark plug hole to find out exactly where top dead center is. You can make a new mark on the harmonic balancer if need be so that you can use your existing timing tab.