On July 24, 2000, Ford updated the 4.0 SOHC with considerable top end changes. I believe this is due to the fact that the 2001 model year Exporer started production in March or April 2000 with the 2000 model year 4.0 SOHC engine. On 7-24-00, the revised "2001" 4.0 SOHC entered vehicle production. The upper and lower intakes along with most of the emmissions and electronics were significantly revised-redesigned.
My questions is: were the heads carry over parts or were they revised to accept the new top end (intake, fuel/air delivery, emmissions, harnesses, etc., etc.).
I am trying to replace a failed pre 7-24-00 engine with a post 7-24-00 engine. Several local sources stated the upper and lower intakes and all related parts can be moved from the early engine to the later engine since the base long block ( block and heads and internal parts) is the same from 2000 to 2003 or 5. However, the pre 7/24/00 lower intake is fastened with 6 bolts per side, and the post 7/24/00 engine lower intake is fastened with 4 bolts per side. Does anyone know if the center 2 lower intake bolt holes on the heads were just covered up with the revised lower intake, or were the heads changed to eliminate the two center lower intake bolt holes on each head?