I have a brand new GM performance parts 880 block that I'm using to build a high performance street 350. After doing a few searches, I found that many guys on these boards are using a Melling M55 with the Mr. Gasket #26 spring with much success, so I ordered this setup.

I then did some research and found out the 880 block was used on 95-2000 vortec trucks, along with the ZZ4 crate motors. From what I can tell, the vortec trucks from those years use a Melling M-155 pump. GM uses part #12555283 on the ZZ4 crate motors.

What pump should I use on my 880 block? Is the M55 even compatable? Will the #26 spring work on all of these pumps?

 

Yes it will fit.

Yes it will work.

The 155 is just a new style of casting; same dimensions and fit.

Melling makes ALOT of the OEM pumps. Wouldn't surprise me, if you went to GM and ordered it from them, and opened the box, and there was a Melling product sitting in that box.

 

Thanks, just making sure. I have noticed a few little differences between the 880 block and 87-93 roller blocks and wanted to make sure I don't miss anything that will give me headaches down the road...