I believe the sender is on the back of the engine. See the enclosed drawing. The arrow points to the front of the engine so you are looking for something on the backside of the engine just off center. I think it is an accurate drawing for your motor. Figure out what has to be removed before you can get to the sending unit and attack it. Remove all that stuff. REmove the clip. Clean around the sending unit. Remove the sending unit. Apply Chevy thread sealer to the threads. Install the new sending unit torqueing to 15 ftlbs. Reconnect the clip. Reinstall the stuff you took off in the first step. In some cases this is a very hard repair to make due to the sending unit being covered up with much stuff. It should run about $150 to have done and might be worth it.