I don't know if it's standard procedure either but just did it because I had to with the type of headers and setup I was dealing with at the time. Don't just assume it's only a carb problem with gas in the oil other causes are a bad fuel pump leaking it directly into the crankcase, poor running engine and a choke that never opens all the way. Here is a picture of the mounts and associated parts from Harold B's site. https://www.firebird400ho.com/mdocuments-library/ in section 6 engine mechanical v-8 figure 6-76