Here’s a rare look inside the Chevrolet NASCAR V8—in this case, one modified to make 955 hp in a street car.

It may surprise casual fans to learn that the Chevy V8 currently used in NASCAR has no connection to any Chevrolet production engine past or present. Nope, it’s not a small-block, big-block, or LS series V8.  The R07 V8, as Chevrolet calls it, is a clean-sheet design built to exploit the absolute limits of the NASCAR rulebook. For example, the bore spacing is the maximum allowable 4.500 inches. And the camshaft is as large in diameter and located as high in the block as the rules will permit to obtain the best possible valvetrain geometry. And so it goes throughout the engine, with every dimension and specification pushed out to the limits of the regulations.

A current NASCAR engine is pretty close to the limit of what can be achieved with an overhead-valve, pushrod V8. But as interesting as these engines are, they aren’t really marketed to the general public, and we seldom get a good look at all the neat stuff inside. So when The Horsepower Monster YouTube channel produced this video featuring an R07 engine rebuild, naturally, we wanted share it with you.

This project involved adapting the R07 to street use (not regular daily street use, of course, more like street use wink-wink) and the result produced 955 horsepower. That’s an impressive figure for any normally aspirated V8, and one more reason to watch. Enjoy the video.