Project V8 RX-7 Update 5 – 5.3L Engine Purchase

About two months ago I was on the fence as to which route I was going to go for the engine swap on the RX-7. My choices were between a 2JZ-GTE, an F22C, and an LS1.

After comparing the cost , power potential, and weight of all three, I ended up deciding on an L33 engine. The L33 is a small block Chevy that is very similar to all LSX engines. The key difference between an L33 and an LS1 is the slightly smaller bore resulting in a displacement of 5.3L instead of 5.7L. One of the big advantages of buying an L33 over an LS1 is the initial cost savings. A lower mileage (<100,000 miles) LS1 can costs upwards of $2000 while an L33 can be found for $1000 to $1500.

Another advantage is that all L33 engines come with either 799 or 243 heads which are equivalent to those found on C5 Corvette Z06s. These are some of the most sought after heads in the LSX community because ported versions are a popular swap for LS1 owners. The L33 also has a lower compression ratio than an LS1 which means it’s more boost friendly (if the project gets to this level). Even with 0.4L less displacement, L33s are rated at 310 HP at the crank in stock trim.

The L33 is found in extended cab 4WD versions of the 2005-2007 Chevy Silverado 1500 and GMC Sierra 1500 trucks. Unlike the LM7 found in other trucks from the same generation, the L33 has an aluminum block.

The actual engine has approximately 82,000 miles and came with a few extra parts worth selling. One of the most noteworthy bonus parts was an Airaid throttle body spacer (the red part seen in the first photo) which should sell fairly easily.

One of the first things we did was remove all of the truck parts that I intend on selling. Once the intake manifold, exhaust manifolds, engine mounts, water pump and coil packs were removed, two of us were able to easily lift the engine onto a stand. The remaining engine oil was drained and the magnetic drain plug was checked for metal shavings. The plug was clean which was a great sign. The crank pulley was turned by hand and the engine turned easily.

Lastly, we removed the valve covers to inspect the valve train and to get them cleaned in a solvent tank. We also removed the hood and drivers side fender from the shell and put the RX-7 on jack stands. This is a really exciting part of the project and I can’t wait to make even more progress in the coming months. The search is on for the parts required to get the engine running and mounted in the RX-7.

Previous posts about Project FC RX-7:

Update 4 – The New Shop
Update 3 – Drivetrain Choices
Update 2 – Interior and Wiring
Update 1 – Engine Bay Preparation
Introduction to the Project