What was H-O Racing Specialties?

H-O Racing sets NHRA National Class Record

From the July 1977 Popular Hot Rodding magazine
article "Winning Pontiac Super Stock Tips -- Pontiac with Punch"

The '74 Pontiac Trans Am Firebird was a very formidable performer even in showroom stock condition. It was equipped with a 455 Super Duty big-block engine that produced gobs of torque in spite of the tangle of emissions equipment. The total driving experience was unmatched by any domestic car in 1974. The 455 TA put performance, handling and style in one neat package. Of all the potential the Trans Am possessed, it didn't seem to lie in the area of drag racing.

Craig Hendrickson of H-O Racing Specialties, Hawthorne, California, pondered over the NHRA rated horsepower, shipping weights, class Indexes and decided that the 455 TA looked fairly promising in SS/KA. That assumption was recently substantiated when Craig set the SS/KA national record at 11.31 sec ET and 118.73 mph. Let's look at what he has done to extract over 500 hp out of the 455 under the limited changes allowed in Super Stock by NHRA.... [Entire 6 page article at the link above.]