ProFlo Performance-built twin-turbo 403-cube LQ9 combo

ProFlo Performance pieced together this boosted LS combo for a customer's '51 pick-up, expecting it to make around 900-1000hp on pump fuel

Photographers: Charlie Sant

The brief from the customer to ProFlo Performance for this boosted LS combo was “a basic, reliable and streetable turbo engine”.

First published in the December 2023 issue of Street Machine

With that in mind, the team built this 403ci mill using factory GM block and cylinder head castings, a hydraulic camshaft and compact 66mm Garrett turbochargers, but none of that should get in the way of it making around the 1000hp mark on pump fuel. With such impressive potential from a relatively simple, street-friendly combo, it’s little wonder that the LS is such a popular platform.

To an LQ9 block, ProFlo added a Compstar crank, BoostLine conrods and JE pistons, while Crow Cams applied a ProFlo-specified grind to the hydraulic-roller camshaft.

Up top, a set of ported LS3 heads feature Manley valves and springs, with a set of factory rockers with upgraded trunnions actuated by Trend pushrods. Cometic head gaskets and ARP studs seal in the combustion pressure.

It’s a good-looking rooster, too, with a billet inlet manifold and valve covers by Shaun’s Custom Alloy. The manifold is loaded with 1100cc injectors and fronted by a Granatelli fly-by-wire throttlebody, both of which are driven by a FuelTech FT600 ECU.

The engine should initially make 900-1000hp on pump fuel at around 18psi of boost, but the owner always has the option of switching to E85 down the track and stepping things up from there. Either way, it’ll be ample grunt to power a particularly cool patina-clad ’51 pick-up, which rides on a Roadster Shop chassis.

“The owner wanted a set-and-forget, low-maintenance, super-reliable street engine for his truck, and that’s what we’ve built for him,” says ProFlo’s Paul Sant. “The guy wants to drive it to work when he can, so while the car won’t be a true daily driver, it has to be capable of regular, reliable street driving on pump fuel.”


In standard trim, GM’s LS-series engines are a pretty rough old thing to look at. According to ProFlo’s Paul Sant, though, prettying them up is a far easier proposition than it once was. “The LS is an ugly engine, but there are so many accessories you can buy off-the-shelf these days that making them look pretty is fairly simple to do,” he says.

This engine has been painted black, but the Shaun’s Custom Alloy billet goodies have been Cerakoted bronze for an attractive, durable finish, and relocated OEM LS coils help matters greatly, too. Other parts like the steam hose kit, Meziere electric water pump, AN fittings, polished fuel rails, and of course the custom ProFlo turbo set-up make this engine a pleasure to behold.

ProFlo Performance
Campbelltown, NSW