This thread is about a new camshaft install and as such the running in is in fact referring to breaking in a new camshaft. It is essential that the correct procedure is followed otherwise it is highly likely that one or more camshaft lobes will be wiped off, the result will mean the engine will run poorly with no performance and the camshaft and lifters will be scrap.
The lobes of the camshaft and the bottom of the lifters must be coated in a break in lube, such as made by Comp Cams.
Cam & Lifter Installation Lube • 8 Oz. Bottle
If the engine is allowed to idle at any time during initial start up damage will likely be done.
On start up engine oil pressure must be verified as good and the running speed set to the required 2000 - 2500 rpm. Constant checking for leaks and coolant temp is required, I use fans placed in front of the car to push air through the rad opening.
If any issues occur that mean the break in period has to be aborted the engine must be shut down, the problem fixed, and then the break in period re started.
The last Rover V8 cam break in I had ran noticeably quieter after around 15 mins as the surfaces bedded in.
As an aside current thinking on running in new engines with fresh bores, pistons and rings is not to baby them but to make them work hard from the off to ensure bedding in of piston rings and not having glazed bores leading to low compression and oil burning.
A 289 Ford engine I had suffered with low compression after 500 miles, I worked it hard and the cylinder pressures came up, I was lucky I caught it in time.
Working hard does not mean high rpms but hard pulling to a moderate rpm and then letting the car push the engine back down again in order to force the piston rings against the bores and not let the rings polish or glaze the bores.