In this action-packed update, we finished up the bulk of our electrical work by finding a home for all of the wires that run into the cabin. Included in this bird’s nest is the drive by wire gas pedal wiring, speedometer and gauge wiring, fuel pump lead, and ECU outputs.

After Fun with Wiring, we plumbed and routed the radiator and heater hose, reinstalled the front and rear suspension, and updated the rear brakes to better slow down all that LS3 horsepower.

Then we put the thunder in Project Thunderbolt by fabricating an exhaust system that will compliment the character of this car perfectly. We based the exhaust on Summit Racing’s Rod Builder Exhaust Kit, which includes enough piping and bends to build practically any custom exhaust system that you could dream up.

I think there’s a good chance we’ll hear this beast run in the next update!

an ls engine swapped into a mazda miata sportscar
big brake rotors and pads upgrade kit on workbench
miata front fender brace for ls swap
miata front suspension with aftermarket big brake upgrade
summit racing rod builder exhaust kit on shop floor
exhaust clamps and parts laying on the floor
man cutting exhaust tubing with a cutoff saw
fabricating an exhaust system on an ls swap mazda miata
dual exhaust system laying on whop floor

Here’s an in-progress shot of the radiator and heater hoses being routed and cut to fit. Once we determined the final position, we clamped and mounted them for good.

Brake upgrades are mandatory when you’re adding 195% more horsepower than the original brakes were designed for. These Hawk HPS Brake Pads and Centric Rotors from Summit Racing will give the rear binders a bigger bite.

These bolt-in braces are a proven way to keep the chassis under control when you are tackling your favorite twisties.

Here’s a look at the front suspension with our new coilovers and Wilwood big brake kit installed.

The foundation of our exhaust system is Summit Racing’s 2.5-inch Universal Rod Builder Exhaust Kit (SUM-670146). It has the building blocks needed to fab up a great custom exhaust.

We also sourced Summit Racing’s Flex Joint Pipes (SUM-642510-1), V Band Clamps (SUM-694250) and Vibrant’s Bottle-Style Resonators (VPE-1795) to finish the front section of the exhaust system.

Fabbing up an exhaust is one of my favorite things in the world—it’s like fiery Legos for car guys.

Here is Summit Racing’s Universal X-Pipe Kit (SUM-642125) in place, which will help the LS3 make good power and sound great doing it.

Here’s the completed front section of the exhaust with the Chevrolet Performance oxygen sensor bosses and Innovate wideband sensor bung in place. I used Dupli-Color’s Low Gloss Black high heat spray paint to add some protection while making the exhaust disappear from view under the car.

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Author: Alan Rebescher

Editor, author, PR man—Alan Rebescher has done it all in a 25 year career in the high performance industry. He has written and photographed many feature stories and tech articles for Summit Racing and various magazines including Hot Rod, Car Craft, and Popular Hot Rodding, and edited Summit Racing’s Street & Strip magazine in the 1990s. His garage is currently occupied by a 1965 Ford Mustang.