The Magnum Monument is known as one of the most luxurious sedans ever built.
It was manufactured from 1976-1991 with very little changes.
The "base model" has a 4L inline six engine, that could use slightly more power for the heavy car, but overall is a great engine. Also it doesn't really matter, as the trim is much more important on such a car and you could have every trim/engine combination you wanted. But there's a thing called "image" or "prestige", however you want to call it.
So there was a V8 powered model, that has adequite power for the car. It was supposed to appeal more to american customers, so Magnum tried to style it a bit more muscular and masculin. With a hoodscope and different rims. And more cupholders and plush leather inside (but you were able to change that.). Many of them ended up in as chauffeur cars for expensive hotels.
You might be thinking "Tim, the V8 is enough and the best engine for that car, nobody needs a bigger engine" and you'd be right. But that doesn't stop rich people from wanting a big V12 and it doesn't stop Magnum from building one. So: there is the Monument V12, making around 400hp (Magnum won't give you numbers on there cars), pushing the car to 270kph and it can drive this speed completely stable, comfortable and constantly if desired. Or you can activate the cruise control at 120/130/150kph and just glide very softly down the road.Whilst being rich. And probably important. Maybe...
In 1977, there was a weird experimental version called the Monument Turbo. It had the straight six, but with a turbocharger, creating crazy torque numbers that only a manual gearbox could handle and that disappeared from the 1979 catalogue after just two years. Test it out for yourself.