AC Delco GM 1104060 Marine Distributor V8 EST Module Sierra 18-5484-1 350 454 Pulley - Crankshaft but they have an extra

but they have an extra area of holes at the top of them where thru-bolted power steering units were able to go as well as  other than that they are the same in every dimension - Typically found on Early Bravo 1986-1991 & early Gen I)

0L 140hp 181cid (1982-some 1992) Should likely be similar to 987784 & 3850799 for the other 1992-1994 models

IA / IB / IC - All Models (1964)

but they do look like they were replaced at some point as usually the stock cap was black on these

Mercury 78277A1 Exhaust Manifold Cover Stamped 78276

AC Delco GM 1104060 Marine Distributor V8 EST Module Sierra 18-5484-1 350 454 Pulley - Crankshaft but they have an extraPart Number(s) Included Stamped 1104060 which is an AC Delco GM Part number J1171 (Marine Grade Rated) General Application Compatibility GM V8 305 350 454 502 using a common EST style ignition module I don't know a ton about this beyond what is stamped on it, but looks like a standard marine GM V8 distributor using the common EST Module and allegedly replaced the following: Crusader PCM Pleasurecraft Marine RA107039D Indmar 556024 OMC 3857400 Volvo