Kit Car Builder, December 2003


PORSCHE’S 718 race car, introduced in 1957, has all the elements necessary for replication. There were only 33 ever built. They were very successful on the tracks. They look cool. They have lots of performance potential today that was never realized when they were produced. You probably won’t have to spend a bundle of cash to build a replica. They are a blast to drive. And their rarity keeps the process at unobtainable levels, except for the extremely well-heeled.

Well, as you can see here, someone else thought that replicating the Porsche 718 RSK was a great idea too. Thunder Ranch has been developing this car for what seems like a long time and it’s a natural progression for this company. Like the original RSK, the Thunder Ranch version is based on a 550 Spyder chassis. However, unlike the original, the RSK won’t replace the other car in TR’s line-up.

headrestThunder Ranch of course has been building a version of the Beck Spyder for quite some time and slightly modified the hefty 3″ round ladder-style frame to accommodate the RSK body. The chassis are powdercoated and designed to use VW suspension components. This prototype turnkey car uses a new VW twin beam front suspension with torsion bars, trailing arms and regular shocks. The rear is also a stock VW torsion tube arrangement fitted with 26mm torsion bars, Thunder Ranch adjustable spring plates and swing arms with tube shocks. It doesn’t take much braking power to drag the little lightweight to a stop – stock drums at the rear and aftermarket discs up front.


Guys like Sterling moss, Ken Miles and Dan Gurney, who drove original RSKs to victory, could only dream of tires the size this replica is wearing – Falken 205-55/16 on 6″ Porsche Fuch alloy wheels up front and 225-40/17 on 7″ wheels out back.

The original car, weighting in at 1,168 pounds, was powered by a 1,500cc 4-cam flattie putting out 142 horses. The ’67 vintage boxer engine in this car was modified and built in house to a displacement of 1,915cc rated at about 115 horsepower. Internally it was outfitted with a 120 Eagle cam, Chevy hydraulic lifters, Mahle pistons and a forged Scat crank. A pair of 40mm IDA Weber carbs sit atop Weber intake manifolds to feed the little beast. Exhaust is purged though Thunder Ranch’s nice-sounding four-into-one pipes exiting out back in the center of the car. The rebuilt 4-speed transaxle is also out of an older vintage and fitted with a Kennedy clutch. Thunder Ranch also included a neat looking Derale oil cooler with a fan, mounted above the transaxle. The company also produces its own 911 fan shroud with integral alternator and fan.

Kit Car Builder December 03 page two

Thunder Ranch