I have this L28 engine, with SU carbs and a supposed Datsun Comp 5 speed. The guy I got it from said the engine was something special, I don’t recall the specific details as it was over 30 years ago, and he is long gone so I can’t call on him to fill me in. 
 

Anyway, I was looking it over the other day and noticed four threaded holes around the oil filter boss. Never seen anything like it before on an L series engine, I even looked at every L series block in my collection (16 or so), and none have this.

It is an L28, N42 block.

Can anyone give me a clue here?

Thanks in advance, Racer

 

 

Remote oil filter mounting bosses?

I thought the F54 block might have those and did a Google.  One of the first images shows the four holes.  Not sure what block he's showing.  Diesel block maybe?

https://www.californiadatsun.com/engine/long-block-short-block-engines/

1982 shows them on the F54 block.  But 1978, which should be N42, is all wacked out.  Seems to show them though.

1976 seems to show them growing in.  Three!

Thanks for the puzzle.  That's weird.

Edited December 26, 20205 yr by Zed Head

Here's my old 1976 N42 block.  Nada.

What the hell is this phallus looking thing on your block?

 

59 minutes ago, siteunseen said:

What the hell is this phallus looking thing on your block?

Head bolt remnant.  That pile of rust was in there also.