Jerry Heasley
July 20, 2010

Our Lone Star Pony Car Saga Continues
Mark Scott's 1999 Mustang GT
Lots of things grow big in Texas, so we're told. certainly, one of those is Mark Scott's vehicle collection. Now, Mark certainly doesn't run one of those dusty, roadside tourist traps that combine a car 'museum' and mini-putt golf course. In fact, all his vehicles run and are exercised on the blacktop regularly. So here's a little puzzle. Mark has eight vehicles with a total of 32 cylinders and three turbochargers. what is the unique feature of his collection?

See, Mark is, by any definition, an enthusiast. Among the cars previously in his possession, he counts a 1965 Mustang, a 1976 Pontiac Trans-Am, an early-'70s Alfa Romeo, a Mitsubishi Starion Turbo and a Porsche 944. Still working on the puzzle? here's a hint-one of them is a Scott Flying Squirrel...does that help?

Anyway, a few years ago, when the New Edge Mustangs were first coming out, Mark fell in love with a chrome yellow GT convertible that was sitting at the local dealership. Once in his possession, Mark started making upgrade plans and eventually settled on installing a Vortech S-Trim supercharger. At that time, the 4.6 liter engine was only a few years new and there wasn't a well developed supply of performance parts. Before installing the blower, Mark's car spun the dyno rollers to the tune of 228 RWHP. This was quite a bit better than previous years' GTs, as 1999 saw the introduction of the PI (power improved) version of the 4.6 engine.

After installing the S-Trim, Mark saw the power jump to 310 on the rollers. In Mark's words, performance car tuning at the time "...was prehistoric by today's standards. The Vortech chip had a flat 10 degrees of timing all the time, with a ton of extra fuel." Mark thought he should be able to get more out of the engine and so he began to research alternatives. Soon enough, he had designed a new, custom intercooler for his car and had Spearco fabricate it for him. New piping was also justified, so he figured it out and had a local welder produce it for him. Along with a set of 36 lb. fuel injectors, Mark headed out to Dallas Mustangs to get a new dyno-based tune. his pioneering efforts were rewarded with 400 hard charging ponies at the rear wheels.

A couple of technical issues remained to be fixed - both the injectors and the MAF were at their respective limits and needed attention. Once those issues were behind him, the drop top Pony gained another 10 percent output. All of this work was still being built on top of the stock intake and internals of the engine. Mark took a break from the modifications scene, thinking he was done with the GT. we all know better than that, don't we?

In 2003, the bug bit again. Filling in his dance card this time were a built shortblock, massaged cylinder heads and a Bullitt intake conversion. The iron block now proudly holds a polished cobra steel crankshaft, Manley forged connecting rods with jE forged pistons helping to push the compression factor to 9.5. The SOhc cylinder heads were treated to porting, including removal of the swirl dams, along with a set of custom ground camshafts from comp cams. The Bullitt intake was ported and port matched to keep incoming air from the BBk throttle body marching along smoothly.

That combination took the GT to a whole new level, recording 530 RwhP and 445 RwTQ. Stout numbers, indeed. Unfortunately, what wasn't quite as stout was one of the valve guides that had found its way into a cylinder head. After about 3,000 miles of life experience, the guide decided to drop down into the cylinder itself. Luckily, not too much damage was done, but the motor had to come apart once more... and that, my friends, is where the real story begins.

As Mark tells the tale, he was then 'talked into' selling off the supercharger and switching to a turbo setup. Now, you and I both know how often any of us has to be 'talked into' doing some performance mods on our cars. More likely, Mark allowed himself to be talked into this, because it all felt pretty natural for him. why do we say that? well, you have to understand a little more about our Mr. Mark Scott from Austin, TX. Remember that collection of his? The one with eight vehicles and 32 cylinders? That's not because they're all 4-cylinder cars. Actually, there's one single cylinder example, a couple of twins, a 3-cylinder, plus a pair of 4-cylinders. Then, there's a couple of V8's, including the GT convertible featured here. So, six of the eight are motorcycles. There's also one more trick. See, two of those bikes are turbocharged, so that would be a power adder that Mark was already pretty familiar with.

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