EngineLabs’ Homegrown Horsepower features have been a huge hit with our readers, and the build offered up today is without a doubt the most “Homegrown” of them all to date. Josh Sperle’s big-block Chevrolet has found a home in his 2-ton 1970 El Camino, but not without a bunch of hard work and ingenuity.

“It was assembled in the spare bedroom of my second story apartment at the time. I had just moved cross country with most of the machine work done and all the parts needed to start mocking it up,” Sperle explains. “We were going to be in an apartment for a while with no garage before getting into a house, so I was stuck. In my hometown, shops were very inexpensive to rent, but I found that wasn’t the case where I moved to. My girlfriend (now wife) told me to convert the spare room into an assembly area so I could continue the build.”

The engine is based on a 454 block bored .060-inch oversize and uses a set of Ross 11.8:1 forged pistons and Elgin H-beam connecting rods swinging on an offset-ground and hard-chromed 6223 GM steel crankshaft, which was pilfered from an old Super Stock engine.

The plan from the get-go was to inject the engine with a dose of nitrous, which had Sperle constructing the engine with that in mind. The piston rings from Childs and Albert have been file-fit with larger gaps to prevent butting under the high cylinder pressures seen with nitrous use. A Crower solid-roller camshaft with .706/.696 lift dimensions and 262/272 degrees of duration controls the valve motion, ensuring that the spent gases get in and out of the cylinders properly. Cylinder heads are ported Brodix BB-1’s that wear triple springs, titanium retainers, and Harland Sharp girdled roller rockers. A ported Weiand Team G intake manifold sits on top fed by a 1050cfm carburetor – which replaced the 1150cfm Dominator that was originally installed. The nitrous system uses a plate and solenoids from Edelbrock.

“Any machining was done in the small storage room on the balcony, including shaping piston domes to fit the chambers and provide adequate piston to valve clearance. Once it was finished and we were ready to move into the house, I needed to get it down somehow. Casters from an engine dolly were removed and bolted it to a sturdy pallet with a sheet of thick laminate on top, and 2″x6″ boards on the bottom as skis. I brought a disassembled cherry picker up stairs and reassembled it, set the engine on the pallet, and with help from friends and family, slid it down a long flight of concrete stairs. It actually worked well, the wood provided a lot of resistance. Once in the house, I installed it in my car that I have owned for 15 years,” says Sperle. 

The car is the aforementioned El Camino, and Sperle has piloted it to 10.50’s naturally aspirated, and 9.50’s on the giggle gas. Although it’s never been on an engine dyno (what true homegrown horsepower has?), using an online calculator from Wallace Racing, he calculates that it’s making in the neighborhood of 700 horsepower naturally aspirated and near 1,000 on the nitrous tuneup.

Big numbers from an engine that was put together in an apartment. Thanks for sharing it with us, Josh!

Want to see your engine profiled on EngineLabs.com? Send a few quality digital photos, background information and complete list of the engine’s components to enginelabs@powerautomedia.com. If you post a YouTube video of the engine on the dyno or test stand, feel free to share it – who doesn’t love dyno videos? We do for sure.