Broken bolt = square paperweight

[Shorty81]

Why does stainless threaded into aluminum make you cringe?

Steel bolts into aluminum causes a chemical reaction. Makes the bolts gall up. Use a good never seize product. I use a 50/50 holy grease and never seize mixture.

 

[wanderinthru]

Steel bolts into aluminum causes a chemical reaction. Makes the bolts gall up. Use a good never seize product. I use a 50/50 holy grease and never seize mixture.

Yes sir, steel does. Stainless Steel does not have the reaction... well grade 308 or better doesn't.... could be wrong on the number, crs, basically if its a grade "good" enough to not have magnetism the aluminum will not react to it.
Moisture is required for the reaction to occur, the grease, never seize etc keeps the moisture out which keeps the reaction from happening. Which in turn makes using it a wonderful idea!!

Edit to add. Stainless steel bolts are great about galling up, ie going in fine but never coming out. And are a Grade AA bitch to drill out. In my experience this happens more in stainless into steel or into stainless, less so into alum. Way I understand this is 2 fold, first the heat sync of the metals alum and stainless are similar, where stainless and cast or steel is not, the stainless will soak up the heat alot faster as well as cool faster making the stainless and steel move at different rates. Where stainless and alum move together...ish. Second is because stainless (most grades) is 'soft" tough as a boot and hard to break (unless its a bolt you need out?) Alum has the same characteristic in regards to "softness" Why the 2 machine similar.
Here again I'm talking about the common grades (308 stainless 6061 alum. I've no idea the grade of an elderbrock intake) Different grades will do different things.
Never, ever, If you are like me and never say never, forget that and NEVER reuse a stainless bolt or nut!!

 

[Bextreme04]

I wanna know too. Im about to use all stainless bolts in my build and quite a few of them screw into the aluminium manifold. I didnt know it was a thing

Dissimilar metals will often have issues with galvanic corrosion. Stainless and aluminum are well known to have strong galvanic reactions. You want to have something separating the materials if you are going to do that, otherwise the aluminum will become the sacrificial material in that combination(especially when exposed to hot water). You had this problem to begin with due to a steel bolt in an aluminum manifold, changing to stainless will keep the bolt from rusting as quickly(up to a point), but you will still have the problem of the aluminum corroding and locking the bolt in unless you put some kind of protective film(like anti-seize or teflon tape) between the two dissimilar metals.