1964 Corvette Coupe: Twin Turbo Build

[_BQ]

Hey everyone,

I thought I would combine a site introduction and a build thread into one and get started over here. The car is a 1964 Corvette coupe that is currently undergoing a 4 month long twin turbo build. This is a pretty massive undertaking (to say the least) that is being spearheaded by my brother. In short, he’s a genius who has forgotten more than I will ever know about cars, with significant experience in high horsepower, forces induction builds and fabrication.

This is version 3.0 of the car. When I got it in 2016, it had a non-original, period correct 327 with a Muncie 4-speed in it. I took the car on the Power Tour in 2018 and long hauled it, but oiling issues ate the heads up and we decided to build a 383 for the car. The 383 was assembled and combined with a Holley Sniper, TKO-600, and (thankfully) Vintage Air AC and version 2.0 was born. We long hauled it on the HRPT again in 2019, and then we did the Emerald Coast Cruzin’ in PCB, FL, in the fall before we decided to go big with this forced induction build which started in January.

Here is the car before we started the new build:











The plan for the twin turbo build was to go back through the motor and refresh everything to withstand 1000+ horsepower. The block accommodates a hydraulic roller setup with LS7 lifters. The bottom end is a forged GM aftermarket crank and should be good up to 1400-1500 hp. The cam is a custom Comp grind. Heads are World Products Torquer S/R with big valves and a bit of port work, but nothing major. Compression on the motor should be right at 9:1. The intake is a Weiand low-rise single plane that accommodates direct port EFI, which will be managed by Holley HP. The throttle body is a Holley 4150 1000cfm unit. Injectors are Siemens 80lb. The distributor is a Holley Hyperspark that I previously used with the Sniper setup.

Here’s a few shots of the motor before it went back in the car. The accessory drive is the new Holley Mid-Mount in satin black. It is an extremely nice piece that really compresses everything into a tight package.







LS7 lifter setup in a SBC:



Oil cooler lines installed above the oil filter:



Motor going back into the car:



And back in its home:

[_BQ]

Fuel system consists of a 450lph in-tank pump with Aeromotive regulator. The tank is a Holley tank made for EFI in a midyear Corvette. All new fuel lines and return lines were run for this build...





We eliminated the stock fan shroud and are using a big Spal fan with a custom shroud. Space comes at a premium in a midyear corvette engine bay and we need all we can get...







My brother is a wizard on fabrication, which you will see illustrated continuously throughout this build. Here’s the new overflow tank for the radiator, crafted to move it back a bit in the fenderwell for more space with a better mounting design:







Ignition box, fuses and relays mounted on a panel which will go on the firewall:

[_BQ]

Fabrication on the hat begins. We had visions of this thing looking like a cross between an old-school Buick air cleaner and the period correct mechanical fuel injection setup. The hat houses air-to-water intercooler cores on each side that will be fed by the turbos. Blow off valves will be mounted on the front of the hat. The water tank that will feed the intercoolers will be mounted in the driver’s side fender well...more on that in a second...

















Here is the hand fabricated water tank. A pump is installed on the bottom that will circulate water to a heat exchanger at the back of the car near the spare tire holder and then back to the intercooler cores. We mounted another small fan on the exchanger for maximum cooling.

[_BQ]

Parts to build log-style exhaust manifold arrived and fabrication on the those and the turbo mounting location began. Turbos are 61mm Precision, with Precision wastegates and BOVs. We anticipate tuning this setup to an extremely conservative 800 crank horsepower until the car receives a new chassis and accompanying larger tires, trans strengthening, etc in Version 4.0. Here are the pics everyone has been waiting for:



















Oil cooler is being mounted in the nose of the car. Heavily insulated lines keep engine heat at bay.





The lid for the hat is one of the pieces of the build that my brother and I were most excited about. I wanted to keep the theme of a stock fuel injection appearance, and this is what he came up with and made:





The lid and section of the hat just under the lid will be blasted and satin clear coated to keep the natural finish. Everything else will be satin black.



Of course we needed stainless radiator plumbing, because of course. They will be powder coated gloss black.





PCV setup is hand fabricated in two units. One under vacuum and one under boost:

[_BQ]

Fabrication of cold side plumbing begins. Charge tubes fabricated and air intake tubes run through the factory radiator support and up into the nose of the car where the air filters are located:











We ran a bigger oil pan to accommodate as much oil as possible. We’re big fans of oil. This pan gained us an extra quart, but the steering linkage just hit the pan. Pan comes off and the solution is fabricated:











We got the hat lid and valve covers blasted and they look like factory cast pieces. Really excited about these. Check them out:





Compared to original valve cover:



That brings us up to where we are today. All plumbing, tanks, shrouds, etc have gone off to powdercoat and we will be wrapping all the hot side components. Engine wiring is left to be done as well as a few other odds and ends before we can turn the key.

Current status pic (that I couldn’t be more excited about:



Thanks for letting me share. I’m stoked about this build. It will be on the Power Tour again this year, if it doesn’t get canceled. If it’ does get canceled, me and some close friends will come up with a tour of our own this summer. Either way, this monster is getting on a road trip ASAP.

[thumper877]

Beautiful car and amazing fabrication skills. I need to borrow ur brother for awhile. Lol

[digitalsolo]

Wow, what a great build! Thanks for sharing!

[_BQ]

Thanks for the kind words.

The exhaust on the car is a bit of a tricky issue. Version 1.0 and 2.0 both used Hooker side exit full-length headers that mated up to a factory style side exhaust pipe. However, because the factory side exhaust was so restrictive, Sweet Thunder made a set of pipes that have a 3” case and 2.5” inner diameter. They’re appropriately named the “GNM”...short for Gives No Mercy. They’re loud and sound amazing.

Version 2.0 of the car was the same 385cid stroker, but with a Comp 282 hydraulic roller. It sounded absolutely fantastic and was truly perfect for the car. When we decided to do turbos, my brother warned me that the sound would change drastically. The cam is smaller, and now the exhaust is much, much different, for obvious reasons. I was concerned about that, but decided the sacrifice was worth it.

Even with the 2.5” inner diameter GNM pipes, we were concerned about power loss due to the design setup. We looked at new side exhaust options to open up the exhaust more. Unfortunately, you can only fit a 3.5” pipe under the factory exhaust covers, an no one makes a good muffler with a 3” ID and 3.5” OD case. We even considered fabricating an open 3” pipe with no muffler at all.

Ultimately, the best option ended up being a set of QTP electric cutouts that will be mounted along the down pipe and under the car. Hopefully now I’ll have a car that’s a little quieter at cruise and on the highway, but still sounds nasty idling along at the touch of a button. Maximum power preserved, too.

[_BQ]

Got parts back from powdercoat today. Everything looks perfect.

Over flow tank, water tank, fan shroud, PCV fittings and intercoolers are satin black:











Air intake tubes and charge tubes are texture black:







Radiator plumbing is gloss black:




Excited to see it all back on the car.

[FLYNAVY53]

Welcome to the forum, and great build! Its always good to see someone else building and driving their C2 as opposed to wiping it down with doilies in a field somewhere while someone else makes sure the color of the stripe on your drive shaft is "correct".

[ryeguy2006a]

All I can say is WOW. That intake you guys made looks amazing and what's more is that it's very functional. That engine bay looks so neat and tidy. Great job, I'm subscribing for sure.

[Interceptor5588]

Pretty awesome

[_BQ]

Welcome to the forum, and great build! Its always good to see someone else building and driving their C2 as opposed to wiping it down with doilies in a field somewhere while someone else makes sure the color of the stripe on your drive shaft is "correct".

Purists going to hate this one. LOL

I’m actually trying to keep a retro feel to the build while simultaneously building a street monster. It’s kind of a delicate balance. I felt strongly about keeping the block orange, not chroming everything out, etc. Guess I’m kind of weird that way.

[_BQ]

All I can say is WOW. That intake you guys made looks amazing and what's more is that it's very functional. That engine bay looks so neat and tidy. Great job, I'm subscribing for sure.

Thanks very much. I’m excited to get it back together now that all the parts are coated. I think we may build a block-off panel to hide the wiper motor and pull the brake booster off and paint it black. I don’t want anything drawing the eye away from the motor.

[RMMiller]

Man, cutting up such a nice second gen Corvette, you're my kind of car guy! Love the car, always wanted one since I was little but will probably never do it.

[_BQ]

The hat is completely finished. The intercooler cores and inlets are powder coated satin black, while the lid and center section was blasted to a natural finish and coated with Cerakote. Twin Precision BOVs mounted.

Couldn’t be happier with how this turned out.

[FLYNAVY53]

oh wow, that turned out beautifully!

[andrewb70]

Very clever design for the intake top! I very much like the intercoolers built into the intake.

What are the two little distribution blocks next to the Bussmann panel?

Are the intercooler cores divided? I would like to know the water flow path, please.

Andrew

[Toccoa]

Awesome workmanship! What type of metal are you using for the intercooler core?

[_BQ]

Very clever design for the intake top! I very much like the intercoolers built into the intake.

What are the two little distribution blocks next to the Bussmann panel?

Are the intercooler cores divided? I would like to know the water flow path, please.

Andrew

Those are high capacity relays. One is for the fuel pump and the other is for the fans.

The intercoolers on each side both have an inlet and outlet on the back. The water tank flows down the driver’s side to a heat exchanger at the back next to the spare tire well and then routes back up the passenger side to the motor in a single 3/4” hose. There is a Y built in there that feeds both intercooler inlets. The intercooler outlets both feed directly back to the water tank in the drivers side fenderwell.