Stick with original motor or new?

[Ms Bright]

I have the original motor for my 68 short bed. I blew a freeze plug and didn't know it and drove about half a mile before it started to smell hot. I towed it home and replaced the plug but couldn't get the dang thing to turn over. It's been wrapped in a tarp for about two months. Where can I take the motor to make sure the blocks not cracked and the heads are not warped? (I'm pretty sure I caught it in time but...) I know that if the motor is ok and just needs rebuilt it would be more cost effective but I'm building a brand new truck. For efficiency, power and coolness factor is a brand spankin new crate motor & tranny the way to go or, ain't it a shame to seperate the original motor from my truck? Also; I'm building this truck to be a daily-driven cruiser with decent gas mileage but with the ability to git on it when the mood strikes. What kind of gear ratio, block & hp should I be lookin at? Sorry if these sound like "girl" questions but I could use some experienced advice. I've been saving up for this rebuild for years so, within reason, money is not an option but I'd like to keep it under around $50,000.