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07/06/2017 at #9000
1969 Chevrolet Corvette LS3 T56 6-Speed Conversion at V8 Speed & Resto Shop
Corvettes all have history, and this clean 1969 Corvette Roadster is no different. It was built in the 4th week of March in 1969 at the St. Louis Corvette plant, and was originally equipped with a 300 HP 350 cube V8 and a 4-speed manual transmission. The first buyer sprung for the fiberglass hardtop for his Monza Red roadster, but other options were limited to headrests for the bucket seats.
As time went by, the original engine disappeared and was replaced by a remanufactured 350, and the car was repainted and fitted with a 427 hood. Polished wheels were added, and the suspension was improved with a composite monospring kit, powder coated coils, front and rear anti-sway bars, Bilstein sport gas shocks, and polyurethane adjustable struts. Wear items were replaced including ball joints, a heavy duty idler arm, new control arm bushings, and a differential crossmember reinforcing kit, u-joints and heavy duty offset trailing arms were installed. The brakes were refreshed with sleeved calipers and a new master cylinder, in about 2001, and our customer bought the car as you see it in 2009.
But by that time, the 350 was showing signs of wear, and the car didn’t run that well. In fact, our customer was only able to drive the car a few hundred miles over his ownership time because it was unreliable and didn’t deliver the performance he wanted.
So he gave us a call at the V8 Speed & Resto Shop where a new plan was made for the Corvette, consisting of more power, better braking, increased reliability and economy in a car that retained it’s classic look. The heart of the recipe calls for a GM Performance Parts LS3 crate engine with Holley EFI and a Tremec T56 6-speed manual transmission from Modern Driveline. Follow along as the V8 Speed & Resto Shop crew complete this transformation and add some additional upgrades from Vintage Air, Detroit Speed, Hydratech Braking, Dakota Digital, Tanks, Inc., Custom Autosound, Wilwood brakes, and MagnaFlow Exhaust, and YearOne wheels.
The purists will cringe, but the original engine and suspension parts are long gone, so this car is being re-built to do what Corvettes are supposed to do… DRIVE!!08/22/2017 at #9076
The existing small block Chevy in the Corvette was in a pretty poor state of tune, we could barely keep it alive long enough to get it on the trailer to bring it to our shop. The battery was dead from sitting, and the float was stuck in the carb. Even after we freed the float, it was not a happy engine.
The car is pretty clean, and the interior is pretty good for a driver.08/22/2017 at #9077
The radio says “Corvette” in case you forget what you are driving, or the badge right above somehow becomes obscured.
We perform a complete inspection on all the cars that come into the V8 Speed & Resto Shop, and here, Trevor checks out the original 4-piston brakes. Corvettes were always known for decent braking performance, but we have plans for better binders from Wilwood on this one.
The car has a few little secrets like this bumper mount ouchie, but it’s intended to be driven and not shown. Maybe some day the exterior will be restored, but for now, it’s all performance upgrades.08/22/2017 at #9078
The bottom side is clean… even though Corvettes are fiberglass bodied cars, you have to make sure the frame isn’t all rusty underneath. This is definitely a good one.
After the inspection, the crew made the plan of attack on the conversion from mundane to in-sane. Well, not insane, but up about 300 HP from the beginning. Sure is a handsome devil.09/18/2017 at #9085
The day came to start the tear-down of the Corvette to get the project rolling. We started on the interior on this on, prepping the works for the Vintage Air A/C install and Detroit Speed windshield wiper motor. Here, Caleb puts his favorite screwdriver to the test.
Corvettes have tight quarters, so working on them can be a challenge. Caleb pulled the sunvisors, then moved to the dash pad and glove “pouch” on the front of the dash.09/18/2017 at #9086
The original heater box came out, as the new Vintage Air system will replace this one.
Backside of Corvette’s center gauge panel. This will be replaced with a Dakota Digital unit.
Removing the center section with the radio and gauges. Note the extensive use of Scotch Lock connectors… these are not very reliable, so they will all be jettisoned and replaced by proper wiring.
Center panel is out, the housing will be reused, but with all new innards. Should be cool.10/01/2017 at #9129Mike ClarkeMember
I may be getting jumping ahead a bit from where you are in presenting this build to us, but, on the V8TV splash page, you show different wheels on this beauty. They look like a larger version of a Chevy rally wheel. Can you dish on these, yet or do we need to wait on an update?10/02/2017 at #913003/28/2018 at #9258
Scotchlock connectors everywhere! The original harness was labeled for reference.
Stock console removed leaving the 4-speed handle and the emergency brake sticking up.
At this point, we’re not sure if we’re going to use the actual original center console or make a new one to fit our new transmission, but we aim to keep the look.
The hood is taped to protect the edges during removal.
Tired 350 looks anxious to come out!03/28/2018 at #9259
The fluids are drained, wiring disconnected, and the engine and transmission were unbolted from the car.
Hooker chrome headers and side pipes removed. The owner wants a set of side pipes, but we’ll have to see what we come up with for the LS3.
Speaking of which, the new GM Performance Parts 485 HP LS3 crate engine arrived safely.03/28/2018 at #9260
This Corvette is a roadster, but the owner also wanted the option to cool off with the help of air conditioning, so we chose a system from Vintage Air to make it happen. Corvettes were offered from Chevrolet with big block V8s and A/C, making a small engine bay even smaller. An advantage of the Vintage Air system is that it was designed to fit under the dash, freeing up valuable space under the hood.
The Vintage Air Gen IV system is mostly self-contained, with the A/C evaporator, the heater core, the blower fan, and the servo-controlled blend doors all in the same unit. This allows for an easier installation and smaller footprint under the dash.
The kit also comes with a condenser coil, brackets, lines, and a reciever-dryer to mount on the radiator.03/28/2018 at #9261
But one of the most versatile aspects of the Vintage Air Gen IV system is the servo controls. These integrated stepper motors are controlled remotely to change the internal cold / hot temperature blend doors, as well as the passages sending air to the floor, dash vents, and defrost ducts.
In this shot, you can see the two white adapters attached to the original Corvette heater controls. Initially, we thought we were going to use this configuration, relying on the original Corvette slider controls to actuate the servo controllers of the Vintage Air unit. However, space constraints with the 6-speed transmission made us choose a smaller Vintage Air controller for the inputs. However, we’ve modified the black knobs by spinning them down to give them an appearance that more closely resembles the chrome-ringed knobs of the original.
The Vintage Air evaporator unit bolted into the Corvette’s dash using the supplied bracket.
Looking at the firewall, the only intrusions are the hard refrigerant lines and the fittings for the heater hoses. Note the block-off plate for the original blower fan in the upper left under the fender.
The condenser bolted in front of the radiator.
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