Well, by lousy head flow, I'm talking about in a racing format. 230-240 cfm is fine, but 300+ was needed to feed sustained 7000 rpms in a 426, 427, 428, or 429 on a NASCAR track. Even though Chevrolet, and GM, were officially out of sponsored racing, Chevrolet still developed full tilt racing engines for use in the Can-Am Series.

Pontiac's Ram Air Series (I, II, III, and IV) were street engines. They were fine at the dragstrip where 5500-6000 rpm could be seen for a couple of seconds, but Pontiac V8's were not contenders in any other racing series. In fact, when Titus/Godsall went SCCA Trans Am racing in a pair of 1968 Firebirds (and later 1969 Firebirds), they used 302 small block Chevys, not 303 Pontiacs.

Obviously Pontiacs are strong enough to run well on the street, and with some work, can run on a road course or superspeedway.

4-bolt mains were not a necessity, but it's hard to explain that to the Chevy guys sometimes, who love to brag about their precious 4-bolt blocks! Nearly all Pontiac V8's used 2-bolt caps, with blocks drilled for 4-bolt. Even Oldsmobiles, which used forged rods and forged cranks in their wicked W-30 and high revving W-31 350 engines, all used 2-bolt mains.

The 426 Hemi, LS6, L-88, ZL-1, Boss 429, and a few other engines, were just in a different league from Pontiac V8's, as far as strength goes. Those engines were designed for racing, detuned for the street, while Pontiacs were designed for street use. That's one of the reasons that in stock, off-the-showroom floor performance, a Pontiac ran as well (if not better) than some of the other more "notorious" cars.