Originally Posted by Will @ M Developments

The YB Cosworth engine is very efficient in relation to the Zetec, the Brake Specific Fuel Consumption is quite different, i can't remember the exact numbers from memory.

There are some Siemens injectors between the 55s and the 83s, they're 72lb from memory, i believe we've got a set on the shelf at MSD.

They should be a nice compromise for you.