A friend of mine has(had?) A 3.91 stroke 4.375 bore hemi that accidentally hit 9800 rpm last outing. Both valve heads in one cylinder went through the piston. Kinda made a mess. The valvetrain failed first. A Hemi spinning 7500 would be a challenge in the valve train department. 10,000 rpm would be insanely expensive.

8..603 156 mph best, 2905 lbs 549, indy 572-13, alky