Need help, advice, and numbers

hey guys please dont be mad at me but im in a huge pickle with my truck which is a 73 chevy ck20 and it was this thread or general discussion i figured id get better help here. my truck has been down with bent push rods and between work and school i havent had a whole lot of time to get new rods in and its been to dark and cold when i do have time. my fear is that when i was wheelin last i lost some antifreeze and trail fixed it with water because its what i had and totally forgot about and am worried that water froze and may have cracked the block or atleast the freeze plugs. i am preparing for a new motor even though itll push back my duster progress the truck is a higher priority. anybody know how much an engine rebuild would be compared to a crate motor, have a shop build a motor, etc. please any and all help is appreciated once again plz dont get mad for a chevy post. thank you in advance