The Aston Martin Valkyrie and Gordon Murray’s T50 both feature very special V12 engines and in this video from Engineering Explained, we discover what makes them so unique.

First up is the engine of the Valkyrie. Developed by Cosworth, it is a 6.5-liter naturally-aspirated V12 that churns out 1,000 hp and 545 lb-ft (740 Nm) of torque, making it the most powerful naturally-aspirated engine ever fitted to a road car. Providing the Valkyrie with some added grunt is a 160 hp and 207 lb-ft (280 Nm) electric motor, bringing combined power up to 1,160 hp and 664 lb-ft (900 Nm). Peak power sits at 10,500 rpm and the engine can rev all the way to 11,200 rpm.

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As Jason explains in the video below, building a naturally-aspirated V12 engine with this much power that revs so freely and is in compliance with emissions regulations is no small feat. In fact, Aston Martin first developed a 3-cylinder prototype of this engine to see if it was even possible.

Then we have the engine of the T50. It too comes from Cosworth and is a V12 displacing 3.9-liters, although it really displaces 3.98-liters, which should be rounded up to 4.0-liters. Nonetheless, this engine revs to 12,100 rpm and pumps out 650 hp. That’s less than the Valkyrie but the T50 actually has 163 hp per liter, more than the 152 hp per liter of the Valkyrie, making it the most power-dense naturally-aspirated road car engine.