Worst I've ever seen as well. Short lived but violent.
http://images14.fotki.com/v221/photos/1/115069/2624009/herbert-vi.jpg?1126208227
YouTube - Doug Herbert '99 NHRA Finals explosion
IIRC Herbert's explosion was the reason why NHRA went 90% Nitro....
Eddie Hill had a couple bad ones leading up to Dougs, I bet they all had something to do with it.
YouTube - Eddie Hill Top Fuel Engine Explosion
I think they had two major explosions close together using cast blocks.
Was Eddie the one who tried the "Indian"-?-modular engine for a short time?