The Porsche 917/30 CamAm car is righty famous fro its enormous power of 1,100 bhp even in race trim.
The Bugatti Vweyron easily surpasses that in road car but with a physically HUGE engine.
Again from Engnelabs is 1,200 bhp turbo 911 bult for Pikes Peak.
Now obviusly it doesnt have to last too long and it probably develops on average way less than 1,200 bhp becuase of the altitiude at the top but interesting nonetheless.
It does make one realise that having a seriously powerful Endurance class is perfectly possible if the rule makers would be willing to back off their hybrid obsession. I'm not kocking hybrids for road or even race use but , at least for a while they are an OEM only car and 90% of Endurance racing has always been privateers.