The Construction Zone - RKSport's

A First Look At RKSport's Blown C5 Project, And A Progress Report On The C5 Shark, Our Soon-To-Be LS1-Powered '76 Stingray

Bob Wallace Aug 26, 2002 0 Comment(s)

There is a world of difference between the construction processes of a corporate project car and one being built by an individual owner, even if that individual is a magazine editor. Time, often in vast increments, is a major factor and necessity in any sort of project. When a company is building a concept or project car to be a representation of its capabilities, it usually can and will devote whatever assets are required to complete said project on the timeliest basis possible.

RKSports' Supercharged C5

What three years ago was cutting edge for C5s is now ho-hum. For example, the December '98 issue of VETTE featured an RKSport customer car both on the cover and over four pages inside. Three years later, that same car, while still attractive and an eyecatcher, is pure vin ordinaire. So, R.K. Smith (the "RK" of RKSport) and crew are once again pushing the envelope, this time with a Millennium Yellow '01 coupe that we guarantee will turn heads and have enough extra power to positively shred heavy-dollar, Z-speed-rated tires.

The RKSportswagen will feature entirely new nose and tail cones, as well as coordinated rocker panels that are heavily influenced by road race-style ground effects. It will, of course, be shod with the latest and wildest in tires and wheels, and the interior is getting re-tailored for both custom and racer looks. And as this is being written, the car is being fitted with a prototype Eaton/Magnuson positive displacement supercharger. We'll have more photos and details next month.

The C5 Shark

Individuals, including magazine guys, have our regular job duties that have to come first. Our personal projects play second fiddle to "making pages" and, in most instances, some semblance of family life. The Lazarus Project, Primedia Tech Center Manager (and former Street Rodder Magazine staffer) Dominic Conti's mid-year roadster resurrection, has spent the past few months in project car limbo while Dom and his wife, Lisa, bought and moved into a new home. Our former Assistant Editor, PJ Rentie, has had to put his '84, The Blubonic Plague, on the backburner as he's learned the ropes in his new career as a teacher.

And then there is the C5 Shark, nee (not so) Great White. With the benefit of 20/20 hindsight, I probably bit off way more than I could chew, project-wise. When we last visited the project in the March '01 issue, I pointed out some of the major differences in engine architecture between the "old-style" 350 that had come in my '76 and the GM Performance Parts gen. III LS1 crate engine (PN 25534322) that I intended to fit into the old Stingray's tight confines. There was also a GMPP 4L60E (PN 1297318) electronically-controlled automatic overdrive transmission that, at the time, hadn't even been uncrated. In our naivete we assumed that since the 4L60E used exactly the same ratios as a 700-R4 and was for the most part a computerized 700, that it could be fitted to the '76 with Bow Tie Overdrives' 700-R4 installation kit, and Scott Leon, a Development Engineer at GM's Mesa (Arizona) proving grounds had shared some info on an adapter plate to link standard 350-type motor mounts to the LS1 block.

There were a couple of minor glitches--GMPP's 4L60 is from the late V8-powered Tahoe, and while it'll physically fit into the old Corvette without cutting up the car, its external configuration differs quite a bit from a 700-R4. That meant not using B.T.O.'s tranny swap kit. And when we started taking serious measurements of the '76s engine compartment and comparing them to the LS1, we realized that the adapter plate idea was unworkable for this particular installation--in other words, complete custom fabricated trans crossmember and/or bracketry and motor mounts were an absolute necessity.

Bow Tie Overdrives is performing both the transmission and engine fitments. They started off by bolting the GMPP 4L60E to a core, empty small-block, then bolting up the core block to the original motor mount "stands" and then went to work engineering an entirely new trans crossmember for the 4L60-in-a-Shark (they're looking at creating an installation kit for as much of this entire swap as is feasible). New motor mount "stands" are being crafted and will be welded to the frame roughly 3.5 inches to the rear of where the originals were once situated. All work is being done around the parameter of retaining the crankshaft of the new engine in exactly the same alignment with the drivetrain as the original 350, as per the factory. Test fittings, once the new trans crossmember was completed, revealed that the F-body spec LS1's oil pan clears the stock power steering ram and that the stock LS1 exhaust manifolds clear the frame, the steering column, and the steering box. Whew! Those same test fittings confirmed our suspicions from a year ago that the accessories (A/C compressor and alternator), when mounted in stock locations low down and tight against the block, will not clear the frame and bits of the front suspension.

So...the LS1 engine fits the Shark engine bay better in some respects than we expected, and hanging the A/C compressor and alternator in stock positions is an impossibility. Coolant inlet and outlet locations are vastly different on the traditional small-block and the LS1; a custom radiator is mandatory, as will be a custom gas tank with an electric in-tank fuel pump and high pressure fittings. It looks as though we have all three situations handled and will go into more details next month. See yah then.

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