Dear Dennis;
The F-290 cam # was right and is the upgrade for the 261 engines (non racing).
You need the heaver springs because the stock ones aren't strong enough for the higher RPM your engine will see (sometimes) etc. As stated; the (tube type) pushrods are a plus too.
Whatever lube you use to assemble will be washed off by the time you adjust the valves & get it on the road. Simply set your idle a little higher than 'normal' for a while is all.
How/why do cams go flat in 200 miles
is anybody's guess. Metal fatigue is probably the #1 cause, I would think.
You have to remember; these engines were never ment to do what "we" make them do. Now & then things just go wrong is all.
Good luck.
