For a stock 390 or 428 that would work, but if/when someone gets into the 500s and up, that 5/16 line into the carb gets sketchy.
I can’t tell if his “filter” which looks to be more of a housing is 3/8 or not, if it is, it’d be a nice setup
I asked the seller and he verified it is the 5/16" filter.
Too bad no one has developed a screw in filter body with an internal cleanable/replaceable filter such as the brass colored “stone type” filter Holley includes in new carbs.
Looks like I will be staying with 5/16" as my power levels don’t require the 3/8"