As it seems I need to replace 1 or more fuel injectors on my 454 Mag MPI 1999 (MEFI3), I am searching for a place to buy some at a good price. The Merc. part no. is: 861260T, but I am wondering whether this is a GM injector so I can buy it cheaper at an automotive parts store ? And in case it is a standard GM part, anybody that knows the GM part. no. ?
Thanks.

That;s not a GM part, unfortuantly you have to buy that one from Merc.

I've got a set out of a HP500EFI but I don't know if they'd be close. I looked but can't see a part number on them. They are in the garage installed in the manifold off the 7.4 MPI that was in my boat.

If you can use them, let me know.

You may want to check with somebody like Arizone Speed and Marine or Whipple. I am sure that they can test them and have plenty left over from upgrades.