Hello there,
Welcome to my project blog! My name is Vlad, I'm a Mechanical Engineer from Toronto, Canada. Please follow me on this quest to convert a Porsche Boxster S roller into a V8 beast!

Boxster V8 conversion

LS1 Harness Rewire

Wiring was definitely the most intimidating part of the build for me when I was doing the initial research, but it’s really not that difficult once you have it all in front of you. For this build, I’m using a 2002 LS1 harness and LS1 PCM. There’s tons of useful information and guides on this online, so don’t be put off by the electrical work.

Here are some good links:



Since the intake manifold is flipped 180 degrees, the original harness layout will no longer work.


My buddy Juan helping me with the harness

The harness stripped and organized. Each plug and pin labeled.

Fitting the harness

SPEC Clutch

I can’t thank the guys at SPEC enough for rebuilding my clutch disc. The store where I had bought it from miss advertised it as a sprung hub, when in reality it was a rigid design. Took only about a week to get my disc back. Shipping it back to the store for a refund would have sucked.

Old Clutch

SPEC Stage 2 Clutch w Sprung Hub

Instead of flexing, the plastic clip on the release bearing just sheared off when I put it in the clutch fork. Not sure if this was a defect, but the plastic seemed much more brittle than on the old one. I didn’t want to take any chances on such a cheap part, so I called Downtown Porsche to pick up a replacement. The guy on the phone told me it would be $260 PLUS TAX! WTF?!?! The whole clutch kit cost me $620… At this point I decided that I’d rather keep my money. The old bearing was in pretty good condition, so I swapped out the plastic sleeve from that one. Not an ideal solution, but hopefully it will do. I did check the sleeve ID for wear and it was the same as the new one.

Good clip

Sheared clip

The tolerance on the SPEC splines seem to be much tighter than the OEM disc. Putting the transmission on was nearly impossible this time; we struggled for a couple of hours to get it on by hand. At first I thought we weren’t getting it into the pilot bearing, but then I realised it was just the friction of the clutch disc splines (yes we did lube everything prior). Once we got some spline engagement, we put a few transmission bolts on and slowly tightened them diagonally. Each time I checked the gap using a vernier caliper to make sure the transmission was going in level.

Throttle Cable

Today I tested an early 986 Boxster throttle cable to see how it would work with the engine. From what I’ve read on other blogs, the cable is too short and the pedal travel only gives you about 60% throttle. The only alternative is to run a drive by wire setup, which requires some fabrication to mount the GM pedal and a lot of money to buy the whole setup. I would have to get a C5 corvette ECU, harness, TAC module, and pedal. This setup is about $800 used if you can actually find it. I was able to find a cable and pedal setup from an early 986 Boxster for $50, so I decided to give it a try first (these are rare, but believe some pre 99 models came with cable throttle).

There are no mounts on the new chassis for the cable, but it’s easy enough to bolt on. The cable is perfect length and you get about 90% throttle without any modifications. If you grind down the pedal stop you can go up to about 95%, which I am happy with. I will have to figure out a custom throttle cable bracket, but that’s pretty much it. The other issue is the space for intake hoses, but thats a whole other project.

Fitting the engine

Today I finally managed to bolt in the engine for the first time. This was a very frustrating experience, especially trying to do this on my own using a set of stands and a pallet jack. At first I thought I could just roll the whole assembly in together and just bolt it all in inside. I played around with it for a few hours and failed miserably. There’s just too many things to get in the way and too many holes to line up in one shot. 

Today I partially disassembled the engine mounts and tried fitting everything piece by piece. This was still a huge pain in the butt, but at least I managed to put it all together. The clearance seems to be pretty good, and I don’t expect to be doing much more cutting. I am a little more concerned about the air intake situation since there’s only 6.75″ of space between the manifold opening and the firewall.

The engine is in

The way it is now, the engine is slightly tilted towards the front. I may have to add some spacers to the engine or transmission mounts to level it out.