Run Stand or Engine Dyno

The blurb below is from Mahle, the piston and ring manufacturer. It's directly from their Engine Break In Recommended Procedures literature;

..."A note concerning engine run stands: They should only be used to ensure no leaks, adjust timing and fuel or break-in flat tappet camshafts. An unloaded run stand WILL NOT properly seat the rings."...

The entire point of engine break in is to seat the rings. If the run stand won't do that without a load, it's not the right tool for the job. If it were me and it was my dollars, I'd keep trying to find a dyno shop to do it properly. There has to be a place within a few hours drive of that area. A chassis dyno could certainly do the job too but you just lose the fluid leak safety net. It's a controlled environment so it's probaby a safer bet than doing it in your garage.

If a dyno is not a possibility at all then put it in the car with the trans, put it on jacktands and have a helper block the throttle open at 2,500 rpm as soon as it fires to break it in with a load. Sure, fluid leaks are a PITA but glazed cylinder walls means the block has to get re-honed and re-ringed. There's also no gurantee you won't wipe a flat tappet cam during break in no matter what method you use.

Pick your poison.