Re: Bolt choice
Tom: It is not wise to use stainless bolts on the head. They need to be grade 8 and stainless doesn't have the strength. Buy new grade 8 bolts and coat them well with silver colored (nickel) anti-seize, or Vaseline petroleum jelly, or silicone RTV. Be certain you also buy grade 8 washers.
You can also coat the gasket holes with gasket varnish to help prevent water weeping through to the bolts but with the anti-seize, this is not necessary. You can use stainless on the exhaust cover. Again, coat well with anti-seize and be certain all bolts are torqued properly to prevent water weeping and repeat rusting.
Yes, galling is a concern with stainless but it usually only becomes a problem with stainless on stainless, non lubricated, and high loads--torqueing bolts and nuts to their limit. You are not doing this. I have galled and stripped stainless bolts and nuts on through transom bolts used to secure aluminum plating. Prevention of galling is also the reason why most usually the 1/2 inch engine mounting bolt nuts are bronze.
Torque the head bolts to 225 inch pounds. re-torque after running the engine the first time. (Long enough to heat it up)
If the exhaust bolts are 1/4-20, then they are torqued to 70 inch pounds.
Buy your bolts from Fastenal if there is one near you.
