For some of us who once were referred to as "baby boomers" (those who were born right after the "big one": WWII), technology can be difficult to embrace. Oh sure, due to perseverance more than anything else, setting the clock on the VCR/DVD player is no longer completely out of the question, and going online doesn't require the help of the 12-year-old neighbor kid. But the truth is, many of us are Stromberg 97 guys caught in an electronically fuel-injected world. But while the winds of change continue to blow all around us, hot rodders can take comfort in the one thing we don't have to learn about at this stage in our lives: the small-block Chevrolet V-8. It never changes, or does it?
The fact is the little Chevy has undergone a number of evolutionary improvements over the past five decades. Graybeards in our ranks probably remember the years the rear cam journal was changed, an oil filter appeared on the block, side-mounts were introduced, and of course when Generous Motors altered the spacing on the rocker cover screws so those neat nine-fin valve covers would no longer fit. The bore and stroke has changed as displacement has grown, and then all of a sudden the dipstick appeared on the wrong side of the block. That was the kind of stuff we had to learn then; today the learning curve is steeper, but the benefits to be had from today's technology are worth it.
Of all the improvements that have been made to the venerable small-block, arguably the most significant was the introduction of the Vortec heads. The Vortec moniker first appeared in 1986 with the 4.3L V-6 and it referred to the vortex, or swirl, created inside the combustion chamber that helped mix the air/fuel ratio to increase combustion efficiency.
Beginning in '87, GM incorporated some of the Vortec technology in the V-8 cylinder heads used on throttle body fuel-injected engines. Of course when those Chevrolet heads appeared with the rocker cover retention screws down the center, it was a sure sign for some that life as we knew it was over. But while these heads looked different, the real Vortec-style heads were not in existence until '96. Loosely based on the design of cast-iron SS Impala LT1 heads (which were based on the aluminum LT1 Corvette/Camaro heads), Vortec heads were introduced on the fuel-injected 350 V-8s destined for pickups. However, it didn't take long for performance buffs to discover the irony that these production heads were better than the popular Bow Tie offerings. The fact is Vortec heads breathe like crazy and make better horsepower and torque than any previous Chevrolet production design.
Vortec heads look similar to any '87-and-later center-bolt head-the ends have the same accessory mounting holes, the exhaust flanges are the same, head bolt patterns are the same, and so on. But while there are similarities, there are also significant differences. From the outside the most noticeable difference is on the intake manifold surface.
The intake manifold on Vortec heads are held in place by eight 5/16-18 cap screws rather than the dozen 3/8-16 fasteners used by the earlier heads. In addition, the angle of the holes are different; on standard heads those holes are at 90 degrees to the gasket surface, but on Vortec heads the holes are at 70 degrees, or almost vertical. With just four fasteners per side, the engineers at Chevrolet were now faced with the problem of how to effectively seal the intake manifold to the heads. Ultimately that was done by coming up with a new plastic gasket with silicone rubber seals around the ports and water passages. And this also brought about a change that old-timers have difficulty dealing with. The intake manifold bolts are torqued to a mere 11 ft-lb, any tighter than that and the gasket are damaged. Chevrolet even designed cap screws with extended tips that bottom out in the attachment holes to prevent over tightening.