At the 2021 PRI Show, with the help of Late Model Engines, we assembled a 427 cubic-inch, all-aftermarket LS engine on the show floor with the sole intention of giving it away to a lucky winner (hence the name, “giveaway engine”). Once assembled, the engine went back to LME to be dyno-tested with the winner’s choice of Vortech supercharger.

When we pulled the winner’s name, Celeste Haskins got the phone call so many of you were hoping for. In fact, we actually interrupted her in the garage, as she was preparing her street/strip project car — a 1991 Buick Roadmaster Estate wagon (who doesn’t love a longroof?!). As we advertised, she was given the choice of superchargers and surprised all of us by choosing the smaller option.

That necessitated having LME remove the V-30 105A supercharger and cog-drive, and instead install a smaller Vortech YSi-B supercharger. Featuring both a smaller volute and a smaller 94mm billet impeller, the YSi-B blower is rated at a maximum output of 1,400 horsepower — 300 less than the 105A. Besides the size and power difference, the V-7 supercharger transmission is much more suited to the street than the V-30, with a less-aggressive step-up ratio.

With a pulley setup designed for only about 11psi of boost from the smaller blower, we had to revamp our original 1,500-horsepower goal. After a quick break-in run on the Superflow engine dyno, LME made the final adjustments to the Holley Terminator X ECU and let the engine eat all the way up to 7,500 rpm. There it made peak power of 1,182 horsepower (with power continuing to increase according to the graph), and peak torque of 856 lb-ft at 6,100 rpm.

All in all, not a bad result with a blower rated at 300 horsepower less, and significantly less boost pressure than we would have been running with a cog setup.