Warren "Rex" Cawley and I share the same name (mine's in the middle), using it only for legal docs. He was a year behind me at USC, and ran plenty of fast 440s and some sterling legs on the Mile Relay, as they didn't have 440 Hurdles in Dual Meets. He looked great at the 50th Reunion a coupla years agos,
Well the team was Williams, Larrabee, Cassell and Carr. The only substitution worth considering would have been for Cassell, whose PR was 45.6 to Cawley's 46.0y (converts to 45.7). Based on their PR's a substitution would have been marginal. Carr already substituted for the trials 4th placer Theron "T-Bird" Lewis. So, another substitution probably wouldn't have even been considered. It wasn't like 1960 when Glenn Davis, second fastest in history prior to the games, was substituted for Ted Woods. Back then there wasn't any changing of personnel from round to round unless injured (and the Soviets in 1980 allegedly made a mockery of that), and Woods and Lewis lost out on what turned out to be their only shot at medals. Of course Cawley ran much better than Cassell did, but it probably wouldn't have made much of a difference. I haven't any idea as to their best relay splits prior to the games, but even with splits I think you'd have ti compare like legs to like legs.
Now that Cawley and Larrabee are mentioned in the same brea(d)th, I'll go ahead and post my impression of their contrasting training styles: Mike would customarily line up with the USC regulars (He was an LA Strider by then) at the start of our 150 yd. straightaway repeats, he'd just keep going into the turn, usually completing a full 330 (something we ran separately, starting on the turn, finishing in the middle of the straight, at a much slower pace than his, 36s vs. ~34).
Rex, at least in my recall, was not there very often--at least in that group of Sprinters & High/Low Hurdlers. Some even wondered how much he trained. Any way you cut it, he was a natural, while Mike was self-made by continuous hard work.He even overcame a busted Spleen, inflicted by some Los Angeles high school student where he taught.
As a fun footnote, we'd always be on the lookout for the Discus ring, at the opposite corner--where Jess Mortensen would perch atop the roller (cinder track) eyeing Rink Babka and Jim Wade (San Diego/El Cajon HS), who was notorious for out-of-sector long tosses. If Rink didn't put it down the center, he could easily skip it onto the track! In fact, at Apple Valley his first 200-footer landed in a trackside trench, obliging (obliging) Officials to estimate the likely horizontal impact spot.