The Vette only had a 6-cyl for two years, 53 and 54, so if your block and head have the right numbers, it's probably worth a try at an eBay sale. Kind of like the 55 model 265 V-8, the one without a block-mounted oil filter. They're scarce, too. You might be able to pick up a core engine at a wrecking yard for low bucks, if you decide to go the rebuilt engine route.
Jerry