Half a century ago they were bolting two motors together for Drag Racing

[Qikbbstang]

the Achilles heel in this motor has got to be the 48" crank and the main caps that support it because they did not enlarge the journals. By the time the power gets to the stern end the cranks got to be twisting and distorting which means clearances are variable not to mention the potential of harmonic nightmare's.. Interesting how he stated they need to turn RPM to save the crank.
     Does it make 5,000HP it's certainly possible with 36lbs boost and power per liter that actually is not that great. There's guys using similar boost from twin turbos pulling over 3,000HP out of a late model modified Ford 5.0 blocks and 4V Boss 302 heads, the part I loved the Ford's using a stock Ford over the counter production crank that goes for all of about $300. It was a cover story in NMRA Race Pages.

http://www.roadandtrack.com/new-cars/a27580/devel-sixteen-5000-hp-quad-turbo-v16-steve-morris-engines/

http://www.roadandtrack.com/new-cars/videos/a27547/watch-a-ridiculous-123-liter-quad-turbo-v-16-dyno-at-5000-horsepower/

[cammerfe]

For more on this sort of subject but with roots at FoMoCo, you might look into Ford's 'GT 90' project.

Created as a concept car for the 1995 season it was offered as an extension of the GT 40 idea. The engine was a 12 cylinder four turbo set-up, created by having Chris Razor weld together the castings from two 'Mod' motors. The crank was a billet done by Moldex.

KS