Logged about 500miles on my newly swaped 400 sb, i sorted all the problems out and had it running great. A day or two later i started it up and a few miles into my drive a knocking started, slow at first and then really rapid. It came and went, and i just decided to drive home and breakout the timing light to make shur it wasnt fireing to early. I got it retimed and started down the road with a slight knocking. the knocking increased directly with the rpms and quieted out as the engine reved. It stared to get real bad, and finialy felt like ther was an air hammer on the side of my block constantly. Starting off first gear felt like third gear, and it needed alot of gas to even idel. I was driving easy and gave it some gas into third and it made a small"clink" nosie and shut off. Now it wont start. You can turn it over and it sounds strange, but 1 of the eight cilinders still fires as it tryes to start. I have no idea whats wrong the timings good and so is the distr cap. Could i have possibly skipped a tooth on the timing chain? or what else could be wrong.

 

Pull the plugs and see if any are damaged
Pull the oil filter off and cut it open to see if it's full of metal

 

Sounds like you spun a rod bearing. Rebuild time..