What you need is the right tool to ensure that the distributor is correctly positioned & timed.

One of these would very likely help out too, at least with engine setup.

As for the pushrods, is it possible that you have 1200/ A12 ones in this engine? That would certainly do it.
The gap at the valve [tappet setting] should be whatever the cam grinder says it should be. Do you know who the cam grinder is & some basic description of the cam. Ideally, you get this information from the previous owner when you buy the engine/ car, not when you can't find him anymore