I replaced the cam in my 454 and noticed that the timing chain looked loose. I installed the cam and finished up the project anyways since it ran great before the install. I brought the #1 to tdc and stabbed the distributor correctly, wires correct etc. It would not start and a slight grinding sound could be heard. I took everything apart and it seems that the timing chain is very loose, more than a half inch of slack. I believe the engine was line-bored before. Would the chain cause a no start? Where can I get an undersized chain and how do I determine the size?