Unless it's a rare? (not sure if they were even offered) big block, it's a 5.7L Chevy TBI or LT-1. TBI looks like a truck motor, LT-1 is a Corvette engine, says Corvette.
Either way 15W-40 and a Napa/WWix 1069 filter for either small block. ATF in the trans, don't remember if it was Dexron III or type F, but the trans aren't too finicky.
FWIW, I used 10W40 most of the time in my LT1 with no issues. More important how often you service the engine/trans than brand or oil weight IMO.
'06 X2 MCX
"I understand why some people may not want to do this the way I have recommended but I can't understand the death grip some people have on a toilet plunger with a hose fitting." -JimN