how hard would it be to get the merc 525 efi kit to work on my 540.790 horse motor what would need to be done. I have a merlin block with alum heads pump gas set up right now.
I would like to convert if not to much involved.
thanks

If it's the standard height block it should bolt up. Have the computer reflashed. Fuel system will have to be upgraded for the efi.

Would also have to replace the harmonic balancer as this is where the crank sensor reads. Probably some other sensor and bracket mods may be required. If it was me, I'd look at other simple bolt on efi systems if you're just wanting it for the efi capabilities. The Merc 525 requires an obundance of sensors and reading items. It would also require Merc computer to work on it. Just my two cents though.