Editing 1994 big block 454

I have a 1994 Big Block Suburban 4x4. I bought it with a spun timing gear. I replaced the timing chain and gears and started the motor. it ran great. I was about 10 miles down the road and it made a lifter sound, like the lifters lost prime. I continued about 8 mile to my house and pulled the valve covers to find 1 pushrod broken. I then checked the lifter pressure and a few were pumped down so i took the intake off. I found all of the intake pushrods bent. I then did a leak down test to see if the intake valves were bent and non were. Whats up? Can any body help?