Making it from billet makes it lighter and gives more options with design. Cast manifolds, no matter how good, will still require substantial work to be "right". Billet intake, properly designed, will be right when it comes out of the CNC.

Those aren't perfect either. For a dual plane crank, there are difficulties getting 5&7 [or 2&4] to behave the same -staggered jetting becomes unavoidable, and that can become a pain when re-tuning for altitude changes. A single carb design buys a little more runner length and faster tuning. The choice basically boils down to the usable rpm range needed, and how much dyno time you can get - in multiple locations.

Speed costs $$$$$ how fast do you want to go !!!!

@@davelewis2174 that is a very stupid answer

@@davelewis2174 I'll bet I can go a hell of a lot faster with a "competitor's" standard "low-rise" single-plane "Dominator-pattern" BBC manifold that not only has an "angled" carb flange to compensate for the "nose up" engine and trans mounting angle of all PROPERLY "engineered" Chevy chassis "setups" for "high performance" so the carb is "level" with the vehicle "at rest" and proper "tuning" is possible but also will fit under a "stock" height cowl-induction hood and "scoop" that weighs far less and has far less "drag" AND underhood and over-carb "turbulence" AND also is "stock replacement" when it comes to being WET with coolant "crossover" passages and a thermostat housing for the "water neck" as well as provisions for other "accessories" like temperature senders, nitrous nozzle "bosses" etc. There isn't a single "history changing" so-called "Chevy" and "stock-replacement" part this "engineer" has come up with that's compatible with anything but "exotic" fuels in "dry-block" applications in "temperate" climates running in "single-pass" so-called "motorsports" and even then his "premium" parts are a joke because most of those "motorsports" require that "stock" engine architecture and geometry be used and the engine "resemble stock" externally at least. And his "engineering" is STILL a joke because it "solves problems" that don't ACTUALLY exist anywhere but the propaganda and minds of "competitors" of "Chevy". Like "symmetrical" cylinder heads for SBC engines which are SUPPOSEDLY "superior" to stock because no valves/ports are "siamesed" like they are in stock heads. Why is "siamesed" supposedly "inferior"? Supposedly it reduces port size, volume and "flow" and creates "hot spots" in the heads. Weird thing is that "symmetrical" port/valve layout in a WEDGE-STYLE CYLINDER HEAD AND SMALL-BLOCK ENGINE ENDS UP "SURROUNDING" INTAKE PORTS AND VALVES WITH EXHAUST VALVES ON EITHER SIDE INSTEAD OF PUTTING INTAKE PORTS AND EXHAUST PORTS SIDE BY SIDE IN THE "MIDDLE" OF THE ENGINE WHERE IT'S ONLY LIQUID-COOLED AND EXHAUST PORTS ALONE AT THE ENGINE/HEAD "CORNERS" WHERE THERE IS "AIR COOLING". EVEN BBC ENGINES WITH "SPLAYED" VALVES STILL HAVE "SIAMESED" INTAKE PORTS FOR THE SAME REASON AND ARE "SYMMETRICAL" IN THEIR EXHAUST PORTS ONLY.

Yeah the first 3 were cast. The last one was billet. CNC machined in 2 separate pieces, clam shelled together in the middle.

What the hell do you think ALL "billets" are? CAST ALUMINUM BLOCKS OF RAW STOCK. WHETHER CAST "NEAR NET SHAPE" AND MACHINED FROM THERE OR MACHINED FROM A "BILLET" CAST NOWHERE NEAR "NET SHAPE" AND "CNC MACHINED" INTO AN "IDENTIICAL" PIECE - WHEN AND WHERE POSSIBLE - MINUS THE "CASTING LINES" REALLY DOESN'T MEAN SHIT ON/IN NON-FORGED "EXTERNAL" ENGINE PARTS AND COMPONENTS INCLUDING CYLINDER HEADS. AND IN FACT CNC-MACHINED "BILLET" PARTS ARE MORE "AFFORDABLE" IF AND WHEN A PARTS "VENDOR" IS PRODUCING "UPGRADED" AND/OR "IMPROVED" PARTS FOR AN EXISTING "PLATFORM" BUT WHICH HAVE DIFFERENT "GEOMETRY" AND/OR "ARCHITECTURE" AND FOR WHICH "STOCK REPLACEMENT" PART RAW CASTINGS FROM AN OUTSIDE "SUPPLIER" WITH ITS OWN IN-HOUSE FOUNDRY CANNOT BE "SOURCED". OF COURSE YOU'LL PAY A "PREMIUM" FOR "BILLET" BECAUSE YOU THINK "BILLET" MEANS BIG BUCKS FOR THE ENTIRE "SUPPLY CHAIN".