I don't know much about corvettes, but I do know someone who put a big-block into one of these 'style' of corvettes. Not sure of the year of his tho, and not sure if any special mounts had to be made... (or mods) And because of his air scoop on it he couldn't put on his hood (or maybe just chose not too!)
His was pushing over 700HP (
lots of goodies under the hood!!) running off of airplane fuel!!!

He broke a couple motor/tranny mounts from the torque before he finally chained down one side of the block to the frame. Later he tried out his nitrous and melted/fried a piston or two!! Other than that he said the nitro ran really smooth considering the size of the motor and all...
Cheers!! Have fun, good luck sellin BBA!!