Mechanical question/bit of an issue here

[Thomas Hoy]

Okay, folk, 
On my new bargain zx900a, I replaced the cam chain tensioner (with another
used unit) That I did not, unfortunately, inspect closely enough. 
Turns out it was kinda jammed, and although it made the cam-chain noise go
away, it was also a little on the tight side, and the springs, well... It
turns out the added pressure on the tensioner cracked off the bottom of the
internal part of the sleeve in which the tenioner rides inside the block.

 Anyway, my question is this:  
I am sure the chunk is stuck in the stator cover area, as it immediately
started to piss off the cam chain as it rattled around, and I shut down the
motor.  Is it safe to plug a new cam chain tensioner (and I mean new, APE)
into the sleeve with the bottom part chunked out, or am I going to have to
replace the whole block...  Note that the break is to the internal portion 
Of the sleeve only, and has not affected the outside.  

I am guessing that it may cause undo flex and weakness in any newly mounted
cam-chain tensioner, and will subject the two allen bolts to more stress
than they deserve.    

It will not be an expensive fix, really, to put in a new block, as I can
pick a nice 6,000 mile block with pistons up on ebay for < $80.00 with
shipping which is probably in better shape than my 25k block anyway, 
But I have never replaced a block before.  
I took the valve cover off this morning and then realized I lack the 8mm
socket I need to pull the stator cover (dunno how, it must have run away out
of my toolkit) and find the chunk.

I am looking for recommendations, a vote, if you will as to whether I 
a.) try it with the block as is, or b.) replace it. 

It doesn't look like pulling the head and block will be too bad, though. 
After I yank the engine from the bike, it looks like no biggie. 

Any ideas or guidance helpful. 

All this happened two days after some piece of road debris killed the 90%
tread metzler that came with the bike...

By the way, if anyone wants an old, half-bondo'd concours tank or 
A corbin g/l for the 84 gpz that needs recovering, give me a holler. 
I have to fund at least a tire, and probably a block and some gaskets ;)