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.

Bow Tie Overdrives
17359 Darwin Ave., Unit C
CA  92345
GM Performance Parts