| I acquired the 1971 Sonett III that was to
become Yellow Thunder in the
spring of 1992. Despite being a northeastern car it was sound mechanically and
carried a modest 61,000 miles. It was cosmetically challenged however, with the
bonnet being a shade lighter than the rest of the car. I drove the car sparingly
over the next four years. In truth, it logged more miles traversing the country in
moving vans than it did under its own power. By the summer of 1996 I could stand the miss-matched paint no longer. I took the car to Euro Sport Auto Body (Springfield VA) to have the bonnet repainted. John Kinter (Mr. Euro Sport) was willing but not eager to shoot the bonnet. His reasoning, the rest of the car was in need of paint too! After two hours of discussion and requisite wrangling, I agreed to a complete makeover. The four month painting odyssey was now underway. I became actively involved. Working at John's shop I disassembled the car, stripped all removable parts from the bodywork and removed the bonnet and door skins from their moorings. John and his assistant, painstakingly hand sanded and rejuvenated the body elements and otherwise got it ready to paint. No domestic paint for this baby! It was shot with Sikens enamel (8 color coats and 3 clear coats). The color is best described as Monte Carlo Yellow and it has a deep and lustrous sheen. The paint scheme is consistent with the 1973/74 factory pattern, black on the rear and hood bubble. The end result was a near show car finish and the birth of Yellow Thunder. In reality, it was surely yellow but it lacked the thunder. [BODY SHOTS] Reassembled and clad with bright shiny new paint, I could see that Yellow Thunder had the makings of a real "looker." I decided to complete the makeover by renewing most of the external fitments. The aged and battle scarred neoprene bumpers where replaced with fiberglass units from Drakenparts. New GT-400 mirrors were fitted to the doors and new lenses and rubber gaskets were installed on all marker lights. The rear hatch was updated with a new gasket and gas strut suspension. [FITMENT SHOTS] It didn't take long to realize that such a beautiful car deserved a performance upgrade to compliment its good looks. I had always wanted to go all out and build the ultimate Sonett street warrior, and I saw this as the opportunity to do just that. I laid plans to upgrade the engine, transmission, brakes, suspension, wheels, tires and cockpit. The engine held the most interest for me. I had built high performance (HiPo) V4 engines in the past, but for this car I wanted to do something really special. After considering various power plant alternatives, I opted for the time honored route of high compression and breathing. The goal was a somewhat de-tuned and wet sumped rendition of one of Jack Lawrence's V4 race car engines (circa 1992). These race engines put out an "honest" 155 HP. [HEAR THE ENGINE]
The car is fitted with a "rally grade" transaxle. A Special 2 gear set is mated to a Sonett ring and pinion (4.67). Compared to stock gearing, first and second are higher, third is nearly the same, fourth is lower. Power is delivered through an open differential. The transmission was completely rebuilt utilizing modern bearing technology and race clearances (optimized for warm weather running). The tranny is mated to the engine through a high pressure clutch and Velvetouch metallic clutch disc.
The interior was made over too. The facelift was a study in form and function. To facilitate mounting supplemental gauges, the original '71 dash (narrow center console) was replaced with a '73 dash. A custom center insert was crafted. In place of the radio opening are three 2 1/16 cutouts for VDO gauges (oil temperature, oil pressure, and water temperature). The lower portion of the panel remains stock. The steering wheel was replaced with a 3 spoke 14 inch Moto Lita unit. The fabric inserts on the seats were reupholstered. Simpson four point seatbelts (driver and passenger) replaced the three point OEM restraint system. [INTERIOR SHOTS] |
In the spring of 1997 I began to build the thunderous V4 engine.
MSS supplied the majority of the go fast parts, many of them "race"
proven. The heart of the engine consists of a over-bored block (+.040) and a nitride
hardened crank. The rod journals and connecting rods were modified to accept FORD
289 (CB 634) rod bearings. The crank and flywheel were doweled and the flywheel was
lightened. The pistons are forged alloy, domed, and provide a 13.5:1 compression ratio.
The engine has been balanced and blueprinted. The heads are ported, fitted with big
valves, and feature dual exhaust ports. A 3/4 race cam was mated to lightweight
lifters. A Solex 40 PII carburetor (2 barrel) and matching manifold complete
the induction system. The balance shaft gear is cast iron and the front cover is
devoid of a fan bearing. The ignition is breakerless, and a MSD-7AL2 augments a
Bosch Sport Coil. Spark is delivered through 8.5mm Magnecor wires. 
The exhaust system is crafted from mandrel bent aluminized steel
tubing. It features twin 1 3/4 inch header pipes with billet steel
header flanges. The flanges are secured to the dual ported heads with 4
bolts. The system is tuned to provide wide banded power in the range 3800-7000 RPM,
peak power occurring at 6400 RPM. The associated primary length is 39 inches.
The header pipes feed a 4 to 1 flat collector which sits directly beneath and is mounted
to the underbelly of the transmission. The exit from the collector is a single 2 1/2
inch pipe which feeds two glass paks (in series). The tail pipe exits in the rear
along the centerline of the car. The second muffler can be removed and a longer tail
fitted in its place for freer flow and added power. 
With the engine and transmission set, Yellow
Thunder was taking shape as a real screamer. What remained
were the areas of suspension, brakes, tires, and wheels (what good is a SAAB that
can't corner or stop!.) I list these items together because I really did approach
their upgrade as a package. I was adamant about changing the external lines of the
car, so all modifications in this area would have to fit under stock bodywork (no fender
flares). The stock 5 bolt hubs and drums were ditched in favor of 4 bolt
equivalents. Custom brake rotors were machined (cross drilled too) and mounted to
the front hubs. The stock single piston caliper was replaced by a 4 piston Wilwood.
The fronts spring are variable rate and provide a ride height 1 inch lower than
stock. Adjustable gas over Konis (99 sport) provide the damping. The front and
rear ends are set up with significant negative camber (the rear was achieved through
bending of the axle). The car is carried by two wheel/tire sets. For
the streets, the car is shod with 6x15 Panasport Lites with 185/65 Yoko AVS Intermediates.
For serious driving, all four corners get 6.5 x15 Minilites and 205/50 BFG
R1s (and yes, this big rubber does fit under the body)