It doesn't really matter what the rate is, the sronger the acid, the shorter soak time. I also used the acid on the carbs (totally dissassembled of course). It cleaned them up real well but didn't get the bodies the way I wanted so I powder coated them. The cast iron throttle bodies are blued/blacked with 44-40 cold gun blue. This stuff requires a good soda soak or they will rust.Always add acid to water not the other way around. Caveat on the carbs, I haven't run them yet so any adverse affects from acid bath or powder coating are as yet unknown, but I don't expect any.
