I almost have my headers in and I want to run the engine without the altonator and fan belt. I want to do this to break in the gaskets so I can retighten the header bolts after it cools off.
Does this make any sense.
Will anything be damaged?
Thanks

 

As long as you keep the alternator wires isolated from grounding out, you should be ok.

 

I don't know how effective it would be to run the engine for 15 or so minutes and then tighten the header bolts as I doubt they are going to walk out. It may take a few days, weeks, or months for the bolts to finally loosen. It is just a good idea to periodically go over them with a open-end and make sure they are tight. Take my friend for example, after almost a year of driving and never checking the header bolt tightness, they finally became loose enough where he trashed his passenger side gasket and this all happened when his car was getting a dynotune. With my car, I installed the headers and made sure the bolts were torqued down real good. After several months, they have not walked out any and I check them every other week.

 

When I put my headers in, the bolts losened up quite a bit so I made sure to retighten them daily for about a week, then I checked them weekly to see if any adjustment was needed. After a week or two they were set and havent losened at all since. I wouuldn't worry about leaving anything off, it is easy to fit a wrench in there to tighten them. Good luck and congrats on the header install