There has been a lot of conflicting information regarding when changes were made to the "sourced" engine in the 1999-2001 Cobras. Fact is that there only seems to be a date that the Windsor-built engine was "phased" into service in these cars, not a complete shift from the Teksid block in a day, or even a week or month. It appears Ford rather indiscriminately sourced the engine from a waiting stock of both model engines that were sitting on the shelf. In order to determine whether you currently have a Teksid or Windsor-built block installed, grab flashlight (or park out in the daylight), open the hood and look down into the "valley" underneath the intake. It's pretty readily visible on these cars. You will see a cross-hatch pattern on the valley that either runs parallel and perpendicular to the fore-aft axis of the car (i.e., a square box pattern), or one that runs on a 45 degree angle to the fore-aft-axis of the car (i.e., a "diamond" pattern). If you've got the square box in line with the front and rear of the car, it's a Teksid. If you've got the 45 degree offset, it's a Windsor-built block.
