can i put a 4.0 sohc in a4.0 pushrod explorer

You may have to do some electronic modifications taking some of the parts from the donor vehicle. 1999 was the first year both the pushrod and SOHC engine was offered in the vehicle. The hookup should be straight forward. Be careful however. The SOHC engine had problems with the cam tensioners, both front and rear. The one in the front of the engine can be changed with the engine in the vehicle. If you have trouble with the rear one in the future the engine has to come out of the vehicle to change it. If that is the way you go, I suggest you change the tensioners on both the front and rear and related parts that are prone to failure.