MerCruiser 70938 66284A2 Front Engine Mount Base 898 228 305 350 1975-1977 Exhaust Manifold You can't install a nylon

You can't install a nylon busing into a needle bearing one ring or vise versa

Someone has painted this black

Usually best to just replace your carburetor with the one that has the same number stamped as yours

Det-Mar (Detroit-Marine) - Black Face / White - Dark Red (Maroon) Text / White Needle

MerCruiser 70938 66284A2 Front Engine Mount Base 898 228 305 350 1975-1977 Exhaust Manifold You can't install a nylonPart Number(s) Included MerCruiser 70938 Engine Mounting Bracket MerCruiser 66284 > 66284A2 Mounting Bracket Base General Application Compatibility MerCruiser GM V8 applications (305 & 350) 1975 1977ish but in most cases are serial number specific so the easiest solution is to just look at the stamped number on your existing engine mounts. (typically only seen on the engine side bracket) 198MIE 898 (SN 0000000 4941054) 228 (SN 0000000 9290290) 280 TRS