The road to high technology is often a two-way street. People who are involved in motorsports maintain that racing improves the breed, from the invention of the rearview mirror by Ray Harroun, the first Indianapolis 500 winner, to the disc brakes and low-profile tires that are commonplace on cars today. But the improvements that are made on everyday automobiles and trucks can pay dividends for racers, too. The extended lifter bosses in the sixth-generation (Gen VI) big-block Chevrolet V8 are an example of production engine technology that has benefited hardcore drag racers. 

     GM engineers lengthened the lifter bosses in late-model small-block and big-block V8 engines to accommodate hydraulic roller lifters. The switch from flat tappets to roller lifters was primarily intended to reduce friction and to improve fuel economy on the highway. It had the additional benefit of allowing faster, more aggressive camshaft profiles that boosted horsepower in high-performance street engines like the LT1 and LT4 small-blocks. 

     When the first Gen VI big-block with tall lifter bosses arrived in our shop, we were dismayed. There weren't any commercially available solid roller lifters that would fit the extended bores. Our first impulse was to machine the tops of the bosses to accept the shorter lifters we'd used for years, but then we realized that would be a big step backward. We recognized that the longer bosses would stabilize the lifters in their bores - a real advantage in big-block Chevy engines with angled pushrods.

Crower stepped up with a redesigned roller tappet with a longer body and a raised tie bar that cleared the taller lifter bosses. Now "long body" lifters are available from many performance camshaft companies. 

When we overhauled the first race engines built with Gen VI blocks, we discovered that lifter bore wear was dramatically reduced. With the old short lifter bosses, the tops of the bores were often bellmouthed after a season of racing. That's because the big-block Chevy's sharply angled pushrods subject the lifters to strong side loads. This sideways thrust is especially apparent in engines with Dart Big Chief and Brodix Big Duke spread-port cylinder heads because they have more severe pushrod angles than conventional siamesed port heads. 

     When Richard Maskin was developing the aftermarket Dart Big M big-block, I recommended that he use extended lifter bosses because of our positive results with this design. In fact, we now use Big M blocks with tall lifter bosses for almost all of our Super Series engines. I was surprised to learn recently that Dart also offers Big M blocks with the lifter bosses machined down to standard height. When I quizzed Maskin about this, he told me that many racers still want to use their old short-body lifters. 

     In my opinion, short lifters are the wrong approach. If a racer is going to spend the money on a brand-new block, he should take advantage of the latest technology that's available. Yes, a set of long-body lifters costs more than a set of standard lifters, but the benefits they offer in longer service life and improved reliability are well worth the relatively minor additional expense. It's false economy to save a few dollars on lifters when you consider the thousands it can cost to repair an engine after a catastrophic lifter failure.

There are also instances in engine design when the racers have the right idea. One of the major shortcomings of the production big-block Chevrolet V8 is its four "missing" head bolts on the intake side of cylinders No. 2, 3, 6 and 7.