Inliners International Forums General Discussion Engines GM 4 cylinders 151 153 181

Beater,
From what I have found you have the jeep/ pontiac/ s-10 version. There are performance heads available for that engine. That engine continued and was used in Fiero's.
Super duty parts were avail thru GM, heads, intakes and everything else.
The head bolt pattern is almost the same as the 153/181 GM engines.
I think they share cams, timing components, front covers .

153/ 181 have the standard SBC bolt pattern on the bell housing. The nice thing with 181's is they produced them currently. I have a few from forklifts with 17000 hrs on them! They are a 4" bore engine. One piece rear seal to. Different heads were used.
The forklift engines used a siamesed intke port head.
Boat engines used both a 8 port head and the siamesed head. I think there maybe 2 versions of 8 port head. There is also a aftermarket replacement head.
Flywheels for 153/181 are the same as SBC for the corresponding 1 piece or 2 piece seal.

The 2 holes on yours is to put the Distributor in 2 different locations depending on application.
Not sure on your flywheel or bell for the 151 you have.