Stainless steel and aluminum are dissimilar metals and will cause corrosion on contact by electrolysis. Bolts/studs are s/s going into mercruiser parts so using antisieze compound is a good idea.when ever a s/s bolt goes into aluminum. The Merchatode system for mercruiser was developed for this very reason. When a s/s bolt goes through holes of aluminum parts a plastic sleeve is the best protection for easy disassenbly in the future. If any of you guys ever took a jet=drive apart, you'll know the reason why there's an insulator between the aluminum intake housing and the s/s wear ring itself. For a while the wear rings are brass now but the kits are still come with the plastic insulator.

Bellhousings usually have dowel pins to align so if you're anal about perfection, you could drill the BH holes larger. find a suitable plastic tubing ,cut it to length that goes through the hole in the bellhousing, slip them on the bolts, grease them lightly and you're good to go without worrying about the bolts seizeing.

+1 great place!

a 316 stainless bolt provides excelant corosion restiance,way better than steel,i use stainless bolts on all external places in a marine application.i buy my bolts from mc master-carr.order by 1pm and usually get them the next day.i keep a nice inventory of ss bolts in the shop.

The SS bolts will be fine. Merc uses them on aluminum intakes going into steel heads. My Merc/Gil exhaust used SS bolts as well.

Like others have said stainless and aluminum are far enough on the galvanic front you can get some galvanic corrosion. You can combat it some with anti seize . As far as strength not all stainless is the same, can't make a blanket statement that's "soft".