Yep, it would be best to just drill/tap a hole in your NA BS cover. Unless it already has a hole there.

 

and if the blocks I have are without the balance shafts
can a machine shop machune the match?

 

you should be able to have the covers bolted on, torqued and line bored. The early blocks did not have this though- they had a separate bearing block that held the balance shaft in and the balance cover just went over that and had a hole in it. The early ones had only 13mm bolts in the front and the rest were 10mm- the laters covers have an integrated balance shaft bearing/ cover and have 13mm bolts in the front and rear of the cover.

 

wow Dan you never cease to amaze me with your knowledge
but i am still confused
i better get in front of the blocks and call you
can you pm me your phn number again
it will be in a week