my 327 on pass side rear reads conv 14 do you know what that means?

If this is the original motor it is most likely a 327. That engine was more popular back in 68. The only way to tell what you have is to get some casting numbers of the block, intake manifold and possibly the carb. You could have any displacement small block in there, its hard to tell from a 302-400 they all look the same from the outside, its all just bore and stroke from within. You may also be able to tell what came original by the VIN number.

If it has the longer VIN, the 8th digit will tell you. I'm not sure when the longer VIN became standard, but I had a '68 Caddy with an 8-digit VIN, although some had longer VINs.