I spent labor day weekend building and installing the new engine in my 55 Ford.It is a 1959 292 bored +030,sealed power pistons,020" off the block,.020" off the heads,rods rebuilt, ARP fasteners on rods,mains,heads and flywheel,new cam bearings,melling oil pump,ARP pump drive ,clevite bearings etc.The cam is an Isky.valves,springs,retainers,lifters,pushrods etc came from John I am using a B intake and a 600 Edelbrock,factory dual exh manifolds.I pre oiled the engine in the usual manner and made certain that I had good oil flow to both rockers.When I started the engine and ran it for cam break in it ran fine.after that I rechecked valve clearance and went for a 10 mile test drive.All went well,never got over 160 degrees and oil pressure was 60 lbs at 50 mph.I got home,looked for water or oil leaks and restarted the engine.It immediately started making the damndest metal on metal screeching I ever heard! I pulled the fan belt,no change so not alt or water pump .I checked for air leaks,didnt find any,pulled the valve covers and had good oil flow to both rockers.Noise seems to be coming from the right side area.I got my broomstick and listened everywhere on the engine.Couldnt locate a specific area.Pushing clutch in did not change sound so not throwout bearing.I got in the car and drove 40 miles to see if it broke.It didnt.Ran perfectly screeching all the way.I had to give it up and go to work.I am wondering now if something might be touching the back of the flywheel?Starter drive not retracting properly? I am pretty sure at this point it is not anything in the engine itself . Any one have ANY ideas?