Who is BS'ing who?

OK, real world, no BS

After putting a stock 71 340 in my 70 RR "back then," it would routinely get over 17 on the highway. Headers, carbs varied between Holley spread bore (new then in early 70's) Quadrajet and Thermojunk

My buddy had a 74 Dodge 1/2T 4x4 short box, big BF Goodrich tires. Dual exhaust, otherwise stock, 360 2bbl. Routinely got 14.5. THINK how heavy and "non aerodynamic" that is. You're talking about 5000-5500 lbs

No, "big" small blocks won't do that "all cammed up." But something approaching the 340/360 factory performance cams sure will.