Project Inferno 408ci LSX


Project Inferno 408ci LSX

There is a good reason for its project name.  this engine caught fire 45 seconds after initial startup.  I used the Procomp polished aluminum intake with matching fuel rails on this engine and the fuel rails don’t have provisions to those the injectors in the fuel rail and the brackets didn’t hold the rail down well enough and pushed an injector out which filled up the gaps in the intake and ran down the back of my motor and across the ground and ran past my foot when I spotted it and as soon as I turned the motor off the fuel found an ignition source.  FORTUNATELY, I had rolled the truck OUT of the garage before starting the motor and I did have a decent size fire extinguisher handy.  Fire did still destroy my wiring harness as well as some sensors, coil packs, plug wires, injectors, hoses, windshield and messed up the hood pretty good.  Cost me about $4000 to fix everything back.   So lesson learned, run the fuel pump FIRST for a while before running motor because.  I wasn’t the only one this happened too.  I had a customer that brought what had to be a $100k 55 Chevy Belair with similar motor with the same intake on it and fortunately for them they had wired their fuel pump to run when the key was on so while I was flashing their computer to begin dyno tuning their fuel rail did the exact same thing but was caught nice and early and saved that car from a similar and I am sure a vastly more expensive fate.


Now to the Details on the build.  I ordered a $4000 408ci short block assembly from  with my options I chose.   Took them 2 months to build the thing though.  I sent out my 317 6.0L heads from the project nitemare engine to Lloyd Elliott. for level 3 porting.  Next was the Procomp intake which I wont be using again for anything but still can’t bring myself to pay $1000 for the FAST intake which would have been a molten blob if something similar would have happened to it.  I modified the intake by porting the 4 bolt LS2 throttle body opening to match the gaskets for the Procomp 101mm throttle body that I bought to go with this setup.  so far with about 1000 miles on the engine, i haven’t had any real issues with the throttle body but the 55 Chevy Belair had the 92mm version could be 95mm but certainly wasn’t the 101mm but anyway we had some throttle return issues with it.  For injectors, i used the 48lb injectors from the nitemare engine project and for camshaft, I used a comp cams 54-477-11 with 227/243 duration @ .050 with .624/.624 lift on a 114 LSA.   Sounds Awesome yet quite streetable.  I actually bought this cam for the 2nd nitemare engine project which didn’t hold up long enough to get dyno numbers for that setup.  Running the long tube headers from the nitemare project and running dual 3″ exhaust back to a dual 3″ in/out x pipe muffler and just turned the pipes down at the rear axle which is a little loud.  I will likely change that to exit behind the rear tire or something. Below 2000 rpms the droning is pretty rough but 2000+ it is much more tolerable in the cab where I can hear the radio fine and such.  Not going to talk on the cell phone in it but with this kind of power under the hood you need to pay attention.

So how did it do, A little disappointing actually.  Torque was almost exactly where I figured it would be at 414rwtq and it actually came on strong in the bottom end which is unusual for LS motors but 4″ stroke 408 certainly makes good low rpm torque.   413rwhp is unusual for a LS motor to make more torque than horsepower as the things love to rev and that cam is listed as peaking at 7000 rpms on the summit web page which I knew wasn’t going to happen with a 408 but figured peak would be around 6300 rpms and this motor peaked just a little early.   With this heavy duty 4L80E transmission with stock heavy torque converter and heavy 9.5″ 14 bolt rear end this drivetrain is certainly soaking up at LEAST 20% but more like 25% which is what I calculated for project towbeast on which I got to dyno a very stock 1991 454SS on this same dyno and that SS has the same rearend and a 4L80E transmission so I could calculate to match the pitiful power rating on that engine.   so that puts power between  517 and 550hp at flywheel and a very pleasing 517 to 552lb of torque at the flywheel.   Here is the dyno graph.

















now that project is completed. I need to move on to other projects. If someone is interested in this truck, I have it for sale. I am listing it on for $29,000. i have spent $24,000 on this truck not including the original purchase of this truck or several other little upgrades like stereo, carpet, interior stuff along the way. That $24,000 also doesn’t include the $4,000 in repairs from the fire damage that the insurance company paid for. That $24,000 is in upgrades to this truck. Engine has 2,000 miles on it and wont be driving it anymore. Only has that mileage to get motor broke in and dyno tuning and make sure no bugs in setup remain. Awesome truck though. My daily driver truck is the plum crazy project truck and I don’t need 2 hot rod trucks.

GM fuel injection for the average guy