We’ve turned the hustle knob up to 11 to get Project Thunderbolt on the road before the next ice age.  First on this episode’s task list are the suspension’s rear control arms, which needed a thorough restoration and some stiffer bushings to help reign in our newfound LS horsepower.

We installed the refreshed rear control arms and the remaining driveline components, then plumbed the brake and fuel lines. Then it was time for the job that practically every car guy dreads: wiring. More specifically, wiring the LS3 engine and then adapting the engine to our Miata’s electrical system. Thankfully, Chevrolet Performance and Summit Racing made that job as easy as possible.

The right parts make all the difference in the world.

painting control arms for an ls swap mazda miata project
control arms for an ls swap mazda miata project
driveshaft for an ls engine swapped mazda miata
a look at the chassis below an ls swapped mazda miata
ls engine wiring harness laid out on a table
a mazda miata with front end with an ls engine swap
thermal sleeves and protection shields on a work table
man wiring up an engine wiring harness

After cleaning up the stock Miata front and rear control arms we were left with a fair amount of surface rust. After scraping and scuffing off the loose rust, we used POR-15 Rust Preventative Paint in Semi-Gloss Black (POI-45404) to keep the iron oxide at bay permanently.

To finish the job right and give our new control arms even more protection, we gave them a few coats of Summit Racing’s General Chassis Enamel (SUM-SP1402). After this step we pressed in a set of new bushings to improve handling and road feel.

Next it was time to run our -6 AN fuel lines, which we secured with Summit Racing cushion clamps.

Take a look at the Miata’s beefy new rear end. Wait, that doesn’t sound right…but it looks so good.

Adapting a more modern engine to a different chassis can be a wiring nightmare. Thankfully Chevrolet Performance has our back with their LS376/525 Engine Controller Kit (NAL-19259261). The kit makes installing an LS engine into whatever vehicle you can imagine much easier. Everything is OEM quality and the instructions are clear and concise.

This is very early on in the wiring process. The towel was there to protect the intake from getting scratched. Coffee and extra strength acetaminophen protected my brain from exploding.

Stuffing a V8 into a Miata leaves little room for wiring, so to keep everything protected from heat and damage, we called up Summit Racing and ordered up a host of HeatShield, Thermo-Tec, and Taylor heat control products.

We love wiring so much…said no human ever. Honestly, it was slow, deliberate work but it went smoothly and was a good overall experience.

Share this Article
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.