That won't happen though. Every old American V8 has a shot timing chain if anyone has been driving it around. It doesn't really matter if it was new a short time ago. It is shocking how fast they wear out, and if it is a stock timing chain, or a "double roller" chain, one that is not also a "true roller" chain, it will have enough slop in it that the Ford shop manual will say it is worn out. This is normal and does not matter. People have no idea because they never take new rebuilt engines back apart unless there is a big problem. By the time the engine comes back apart for another overhaul it has 100,000 miles on it or more and nobody is surprised the timing chain is shot. They have no idea it has been that way since 10,000 miles. You need to know it because when you test like this you will probably SEE it. It will be significant, but will not be close to a whole tooth.
so true i work in a auto machine shop and do assy. we have a run in machine and from the time it goes on and comes off the machine you can tell it is not as tight as before the run in . also line honing the mains dose not help as it shortens the center to center between the cam and main bores . and yes they do make shorter timing chains for just that but who has them , who stocks them and why bother . when i get one that's got a lot of slop i say hey look this one has centrifugal timing . like homer says WHAT ARE YOU GOING TO DO ? but i always like the SPEED COST MONEY HOW FAST YOU WANT TO GO ? so if your a real whiz bang get the 3 slot key way crank sprocket [or broach your own] put it at the 4 deg. adv. a add a 3.8 L buick v-6 timing chain tenninor to take the slop out of the chain or hell go boat motor gear to gear with a cam to match right rot. you can just keep going tell you end up with a swiss watch of a car