IM bolt removal - 83 5kt non-quattro

[Tex Terry, II]

I removed the throttle plate section and , as luck would have it, I could
not see the lost part in the top of the IM (using mirrors and flashlight). 
I have been able to remove most of the allen head bolts on the IM ( I have
to remove the IM to find the bolt with the hose on it that I used as a plug
in the cold start injector hole, which was sucked in to the IM).  I am
having a problem with the allen wrench shaft seating completely in one
bolt.  I have not removed the exhaust manifold pipe from the turbo.  I am
thinking that I might be able to  tap the allen shaft into the bolt head,
but I want to ask for any suggestions first.  I am using the allen wrench
short shaft on a 3/8 drive.  These bolts take a 6mm allen wrench (hex
wrench).  

Thanks,  Tex Terry, II
1986 5kt auto non-quattro 4 dr sedan
Franklin, PA