Chev 51-
Welcome to the Stovebolt. Your question is one many of have pondered and I suspect you'll hear a range of responses. To drop in a Chevy V8 does not require a front clip, but alteration of the engine mounts and transmission mounts. You may want to switch transmissions and rear ends while you're doing this swap. Some further choose to drop the entire drivetrain from a donor vehicle into the truck. If you're committed to the V8, this is a straighforward swap. A full drivetrain swap will give you power and less vibration at highway speeds.
Owning a '51 as well, I pondered the spectrum of choices and opted to go with a new front clip. For me, I wanted to gain better front suspension and power steering. I'll enjoy the smoother ride over bumps and the misses in my house will have an easier time getting the steering wheel around. I knew that it was a much bigger can of worm$$ to open and it would take longer to get on the road.
So in the end, you can choose to drop in the V8 and call it good, getting you right on the road. It's much more work, but you can choose to graft on a front clip and/or switch to a modern drivetrain. Other components could be added later, after you've had a chance ot get a feel for the truck. Think carefully about the time and expense. The choice is yours. There are some good tech articles here you should read as well.
The good news is that you've come to the right place for advice (and jokes and politics...). Folks here at the 'Bolt will keep you rolling and freely offer their expert experience. We look forward to hearing more about you decision and progress!
