My freind just installed a 350 and a new 700r4 in his camaro.He had a clearance prob with the tranny so he had to do some grinding on the tranny case by the #8 cyilinder.Mind you he never plugged the spark plug wholes. When i got there i saw very fine metal shavings on the inner fender but i saw none on the motor its self. For good measure i stuck a vacum cleaner hose on the #8 spark plug whole and then tryed to stick a magnet in the whole and nothing really came out. He got the car started and got the cam broke in and everything seems good. If there was some fine metal shavings in the cylinder would they just blow out the exhaust ?????

 

yep. Maybe score up the cylinder walls a bit, but there's nothing you can do about it now. With the teeny amount he may have gotten in there, I think you're fine.
As always, keep an eye on the oil pressure, and fluid levels for the first while. And of course after 100miles or so, remove the rocker covers and make sure all rockers are moving (ie, you didn't "lose" a few lobes on the flat tappet cam )
checking the plugs is probably a good idea too.