High milage engines can stretch the timing chain so far when you rev the engine the chain is actually forced out against the timing cover. Sound just like bad rod bearings!
IMHO only; there's nothing wrong with the Nailhead, they are in some cases far more robust than the next gen engines. Sure, they don't breathe as well, but they oil better. Buick engines are well built from the factory, so there's usually no catastrophic parts failures that are much more indigenous to cheaper marques. Swapping out a Nail and loading ina later 455 will in most cases ruin the resale value of the car. Sure, the 455 is much more powerful and smoother, but the Nail has cachet, and people pay for something unique, - as long as it runs. Having built a couple of Nails over the years, yes, there are some different tricks to them, and they are not like "mainstream" engines, but they aren't rocket science either. A smooth running nail can easily be as nice as the later engines. As in a previous post, the conversion process isn't as easy as it looks. There's a lot to it, and it might be easier for you to trade off that 455 for a healthy 425 or 401. As I said, this is just my nickel's worth.
Joe left, another sign that threads about religion and politics don't work well on a board like this.... :ball:
What ever you do not replace that nailhead with a big block Buick engine,,, 1966 Rivs came with 425's,,,, and switch pitch transmissions.... It costs nothing to tear down a engine and inspect it... that is the best thing to do.... it is far easier and less expensive to completely build the nail than to swap out both the engine and trans and drive shaft and the radiator /fan /fanshroud assembly of a big block.... first do a very good check out on that engine and then start rebuilding... check out my list of cheap tricks and the Doc mod stickys and go from there....
