Difference between 4.3 engine 090 block and 090M block

[billbayliner]

Bought a remanufactured 4.3 long block. Was supposed to be in stock BUT after calling today they inform me that they have to build it and said Friday shipping or Monday....

Well I'm not holding my breath on that one........

So now I am going to plan B JUST in case the shipping is delayed.....

Going to rebuild my engine but I need a block because I do not want to bore the one I have as it is already bored 40 over.

My blocks casting is 090. I cannot find a 090 but a local auto recycler has a 090M block.

Now here is the question...... What is the differences between the blocks? Will all my parts from the 090 engine fit in the 090M block including all bolts and hardware?

Someone told me that the motor mount locations were different. Also told me it needs metric starter bolts.

Thanks in advance.....

 

[achris]

M=Metric threaded holes. Very few of the screws you currently have will fit.

Chris...

 

[Scott06]

the 090 M block uses metric M10 threads for the following

flywheel cover bolts and studs (2 studs for ground wires)
starter bolts ( starter will work just need correct metric starter bolts)
side motor mounts depending on how your fuel filter mounts two of these may be studs

a decent old school hardware store will have most, i got the grade 8 studs from mcmaster carr and bought the starter studs off ebay

the rest of the fasteners were SAE 3/8-16 so had no issues swapping over all my accessories.

 

[nola mike]

starter bolts ( starter will work just need correct metric starter bolts).

My starter wouldn't work. Metric bolts (m10?) Were slightly bigger than the holes in the starter. Probably could have drilled them out, but decided to swap out with a PMGR starter

 

[achris]

The U.S. is inching its way toward metrication.

 

[Scott06]

The U.S. is inching its way toward metrication.

this is more like GM inching its way to insanity. I can understand one or the other system but to have some fasteners metric and some inch on the same block is goofy.