318 draw through build

You should not assume because the ends are infact flared. I own and use a press flaring tool. Every hard line to soft connection I do on every car I work on has a bubble flare behind it. I don't see how you can call quality rubber fuel line "cheap ***", but then again you could be one of these guys who puts braided line to his windscreen washer bottle hose.. :) Spending big bucks on blingy braided line that doesn't "look like ****" doesn't make you more professional, choosing the right part for the job does. Most times it's total overkill for the application.
The cut carb feed line is only there to make it easier for me to do some tuning. It's actually the one I've used on other engines to do this over the last 10 yeas or so. It is also bubble flared at each end under the rubber line. Once I'm happy with the tune it will be replaced with a hard line.