I just bought a 406 small block, blanced and blue printed. i used all the bolt on parts from my old engine to finish the new one(no internals). i got it all installed and had my mechanic look it over because it wasnt running right. he ended up replacing the cam because it went flat for an unexplained reason. It was running good untill the other day my starter went out. I switched starters and it was running fine all day untill i got on it. it started to peel out and i heard a clunck and lost some, not alot, but some power and now theres a real high pitched skweek. I cant even tell where its coming from. does anyone have an idea where to start looking?

 

Is the 400 internally or externally balanced? Make sure the flex plate and harmonic balancer are correct. Did you tear the engine down to remove the metal from the camshaft? It could be related to the starter sticking somehow but I would be afraid the camshaft metal went into the bearings. Probably something simple like a starter sticking or a belt problem if you cant find anything pull the oil filter dumpit out till almost empty then dump it out over some paper towels then cut open the filter and inspect, any larger metal "feel between fingers"or any brass looking stuff is bad. I ran through to cams this summer been through the drill dont let anyone kid you once you lose a lobe the metal went somewhere.