Grantelli Motor Sports (GMS)...
Grantelli Motor Sports (GMS) installed this monster 297ci engine in an '07 Saleen owned by Troy Coughlin of Jeg's Mail Order. It roasts the tires with 585 rwhp, through an automatic transmission. That works out to roughly 702 hp at the crank-on pump gas!
Granatelli Motor Sports (GMS) has been a name synomous with Mustang performance for a long time. Not only is owner Joe "JR" Granatelli a prominent figure in Mustang drag racing and parts manufacturing, his family racing lore goes back decades.
GMS has been in the S197 market since the cars hit the streets and continues to develop products to enhance and improve the vehicle. The company started with suspension upgrades, and then released various electronic and digital controls. GMS recently expanded its reach by releasing a turbo system capable of 800-plus rwhp, with optional upgrades.
Keeping with diversity, GMS began selling CNC-ported cylinder heads for all types of modular engines last year. This year the company is keeping the aftermarket well-supplied and announced a new line of crate engines.
"We collaborated with Ken Duttweiler of Duttweiler Performance to bring modular crate-engines to the market," commented JR Granatelli. Not only can you buy virtually any bolt-on part for the Three-Valve engine from the company, but GMS can also supply a fully built engine to go along with its other parts. The engine ultimately found its way into one of the company's project Mustangs. We ventured to the GMS headquarters in Oxnard, California, to get the lowdown.
"Mod motors love boost," proclaimed a proud Granatelli. This is a guy who should know since turbo technology and boost are engrained in his family history.
GMS took a stock Three-Valve...
GMS took a stock Three-Valve block and bored each cylinder out to 3.552 inches. These blocks are quite durable and more than adequate for this turbo application.
For those who aren't aware, Granatelli's father and uncle were acclaimed racers and car builders who, with Mario Andretti at the wheel, won the Indy 500 in 1969 with a turbocharged combination, promptly leading to a ban on turbos for many years. While Granatelli was only an infant at the time, the technology and racing heritage was a way of life.
He worked at Paxton Superchargers in high school and college. Granatelli even owned an Indy Car team from '87-'92. He sold off his portion of the team and purchased Paxton Products, where his pet-project was the first 50-state-legal, 1,000hp-capable supercharger, dubbed the Novi 2000.
The owner of GMS provided insight into the boosted mod motor realm: "Mod motors absolutely love forced induction. Most overhead valve (OHV) motors do. The mechanical advantages of twin-cam and four-cam engines are endless. More importantly, and to the point, a mod motor gains more power per psi of boost than a conventional pushrod motor.
It is a tedious process, but...
It is a tedious process, but each ring is put in the bore, measured, and then proper ring gaps are cut using a special tool on the bench.
Speed-Pro main bearings are...
Speed-Pro main bearings are installed and lubed with Redline assembly lube.
Chris Gunter lays the 3.750-inch...
Chris Gunter lays the 3.750-inch stroker crank in place.
The main caps are bolted down...
The main caps are bolted down using four main cap bolts and two side bolts. Each is torqued into place, Gunter uses a digital Snap-on torque wrench to accomplish this task.
One great feature with this...
One great feature with this block are the factory-supplied four-bolt main caps (at right), which also feature two side bolts. That equals a total of six bolts for each main cap.