Non-HO (Renix) Block Casting Change?

I've searched the forum and my manuals and can't find the answer to this one. The 4.0 in my 89 XJ has 5 - 2" freeze plugs on the manifold side of the block. The replacement engine I bought, which was already out of the XJ, has 3 - 2" freeze plugs and 2 - 1" freeze plugs between them. This engine still had all the Renix gear on it and I was told it came out of an 88 XJ.

So, did the block casting change between 88 and 89, or am I looking at a 4.2l engine? Everything seems to be the same other than the freeze plugs.

What's the casting no. stamped on the driver's side of the block? If you can give me that, I'll identify the block for you.

Hey Doc,

Drivers side: first is 08 6 87 (which I'm guessing is the date cast) and then EF8933002665BT

Passenger side: (stamped, not cast) 704M16

Thanks,
Tom

The engine no. 704M16 means that it's an M block (4.0) that was cast on 16th April 1987. The casting no. EF8933002665BT is that of a renix 4.0 block.

Thanks Doc!

Tom