Tech / Tech Projects

Project Thunderbolt LS Miata (Part 6): Clutch Install and Final Test Fit


The is the Chevrolet Performance T56 Magnum Transmission Installation Kit (NAL-19301625). It includes the bellhousing, flywheel, clutch and pressure plate, hydraulic throwout bearing, fittings, and hardware. It’s like Legos for gearheads.

The clutch and flywheel assembly is torqued to spec and ready for a life—cough, cough—of gentle, low rpm granny shifts and trips to the grocery store.

A tale of two six speeds. While the Mazda transmission on the right may look vaguely similar, the T56 Magnum is a heavy brute, with a strong gear set and a bellhousing that dwarfs the stock Miata setup.

Since the T56 transmission weighs over one hundred pounds, I used my engine hoist and load leveler to mate it to the LS3 engine.

Here’s our engine and transmission assembly mounted to the car with the radiator, AC condenser, accessories, and headers in place.

Part of the final test fit is to locate the frame rails and transmission crossmember.

The test fit went well, so the engine came out and all of the modified areas were stitched up for good. The interior firewall braces were also welded back in. They required a little massaging given the new shape of the transmission tunnel.

Welcome to Part Six of Project Thunderbolt, our LS Miata swapfest.

In this update, we’re ready to mate the Chevrolet Performance LS376/525 engine with the Tremec T56 Magnum six-speed for good. But before we could join them in mechanical matrimony, we needed a clutch that combines excellent holding power with great drivability.  Summit Racing came to the rescue (again!) with a Chevrolet Performance T56 Magnum Transmission Installation KitFrom the bellhousing to the dust covers, this OEM quality kit includes everything needed to get this important job done right.

Once the engine and transmission were bolted together, we lowered the whole assembly into our Miata for the final test fit. This step was necessary to locate our transmission crossmember and frame rails, and to make sure all of our chassis modifications have been done properly. All of that checked out, so we removed the engine assembly and welded together the modified firewall area, transmission tunnel, and interior.

Now we’re getting somewhere!

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  1. Larry Locklear says:

    ENGINEER, you should visit with Chip Foose!!! This is quite the hot rod project you or whoever has chosen, but you are definitely up to the chore. You are young and have great skills. I am impressed!!! Keep up the great work. Larry

  2. WOW! That’s one awesome engine swap for such a small car. I know it will be one wild and exciting ride on a short wheel based Mazda Miata.

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