Hi Maynard,

Heating the part allows RPM to flow out when applied with the brush( which we supply with the product). A heat gun or hair dryer will provide enough heat to warm the part. We have used RPM on the head pipe of Project Valiant for corrosion protection. Exhaust manifolds are a completely different heat profile approaching 1000 degrees and while we haven't tested this area I would have reservations.

We have several people reporting they have used RPM on aluminum carbs ( AVS-AFB) to prevent that white corrosion on aluminum. RPM works great on suspension, cast and stamped parts plus sheet metal in the bare areas under the dash and shelf panel. Got a set of non coated aluminum wheels? It works great to retain that polished look that goes away so quick with out protection.

Thanks for the question
PS - always great to have a shout out to a fellow GTS owner( LS27P9B)