How Stef’s developed first crankcase vacuum pump kits for drag racing engines

Written by Moore Good Ink

One night in the dyno room at Jenkins Competition in the early 1990s, engine builder Gary Stropko and shop foreman Stevie Johns were discussing the merits of scavenging the gases from John’s Competition Eliminator engine and wondered what might happen if a vacuum could be applied to the crankcase. So they asked Bill, or “Grump” as they called him. “Yeah,” said Grump, “You could take an air injection reaction pump and modify it to create a vacuum.” He went on to describe exactly how to accomplish the task, and Stropko scrupulously followed his advice. “It was worth a ton of power and soon we realized the more vacuum we created, the more power we made,” bridled Stropko. “Moreover, we were able to exploit the advantages of running lighter rings and less ring pressure.”

At that time Joe Stefanacci had recently formed Stef’s, specializing in custom and production racing oil pans, a trade that had occupied him since 1974. Joe knew about the crankcase vacuum pump innovation, and asked Bill if he would allow him to build the kits and sell them. But Bill had him sworn to secrecy and asked him to wait a year. One year later Joe again inquired if he could produce the revolutionary kits. Bill said, “Yes,” and Stef’s began developing and supplying the first complete crankcase vacuum pump kits for drag racing engines. Today Stef’s news is of the first complete oil filter adapter kit for LS engines with aftermarket steel oil pans. Like the crankcase vacuum pump kit from the early 1990s, it is unique.

Read about Stef’s unique oil filter adapter kit here.