I'm confused, on the silver tops, you insert a locking pin into the block, along it's exhaust side at the bottom of the block you will see a 10mm headed blanking bolt, a pin goes in here, and the crank web, has a flat on it that contacts this pin, it is a BLACK coloured pin, get the engine to tdc, rotate about 15 degrees or so COUNTER clockwise, when looking at pulley, the insert pin in crank case/block, rotate till it(crank) contacts the pin you'll hear a definite ping sound if the plugs are out, now check bar fits across cams.
As for the noise, were the tappets empty to start with, they should have been anyway, how may mile shave the tappets done ?, why not take the tappets apart and clean them out ?
tabetha