Good ol' I6 or a New V8?

[gread]

My current '67 half ton has the I6. It has never done me wrong, but it seems like getting a V8 is the thing to do. I am intending on getting a new transmission, but should I put in a V8 as well? The purpose of my vehicle is general driving, moving, hauling of small loads (nothing beyond a one-horse trailer). I also here that newer/fuel injected V8's get slightly better gas mileage. Is the V8 worth the money, or is sticking with the I6 a better idea? Thanks in advance for the input.