Welcome to the forum! I also recently acquired my first stovebolt, and it's a '55.2 6400 like yours. My brake pedal goes straight to the floor, and doesn't even come back again. I got its 261 started with fresh gas in an auxiliary can, new points, new condensor, and a new filter. I'm in a similar position as you, just haven't had time to tackle the brakes. I don't think it's something I'd hand off to someone else. You can learn it, and there's plenty of folks here to guide you. More importantly, it'll familiarize you with your own truck, which will be invaluable when it acts up in the future.
If you want to make sure it's a 261, just look for the "captains bars" in the casting, or post your casting number (found on the passenger side of the block) and we can look it up. Here's what mine looks like:
261 casting number Also, I think the terms Apache/Viking/Spartan didn't come out until '58, when they got the dual headlights. What you have would certainly be a Viking though, if it were a couple years newer.
