I bought a 77 Malibu, they guy said it is a 350. Iwrote down the casting number, and looked all over the web. I can find what size it is. Here's the numbers 46077, or 46877. The casting where the 0 or 8 is is messed up from when it was casted. Any help would be appreciated. I have a gut feeling it may be a 305.  

Block casting numbers are at least six digits. The first five digit code you gave is included in three 305 engines that are casting numbers 460776, 460777, or 460778.  

Thanks for the info. I eventually found the casting numbers online. I should of checked but trusted this guy to much.