GM can't make an oil cooler line that won't start leaking after a few thousand miles. you could use a factory cooler and make up some custom hardlines with aftermarket braided flexible lines or something. the cooler in my 94 cop car Caprice is pretty big, but the lines leak a bit where the flexible line meets the hardline off the engine block.
1971 Nova(looks like 69 camaro from underneath!)
355sb, vortec heads, HOT cam,T-10 tranny, 3.70 gears 16X8" IROC wheels. 12" Corvette brakes on the way.
see pics here http://community.webshots.com/user/novaderrik