Swapping this 350 into an 85 El Camino in place of the 305. Does it use the knock sensor? What is the thing above the oil filter? Big thing that sticks out, do I need that? Both holes are blocked with a pipe plug right now on the 350, just want to make sure I do or don't have to put them on.

For now it's retaining the stock CC Carb and HEI ign.

 

If the stock CCC system used a knock sensor, you'll have to use one too. The knock sensor is bore-specific, so you'll need to replace the 305 one with one for a 350. The thing above the oil filter is the oil pressure sender and/or switch, you'll want to keep that too.

 

Thanks for the heads up, I'll have to go the store then and grab a knock sensor.

If that is the oil pressure sending unit, then what is the deal on the top rear of the block?

 

Im thinking just "thinking" thats where they used to be located on older models but were then relocated to above the oil filter. I "think" i heard that somewhere or something like that.

 

If you have both, then the one on the top of the block is the sending unit and the one above the filter is the switch.

 

OK yes I have both. I know what the sending unit does; but what does the switch do?

 

I don't know anything about El Caminos, but if it's like a thirdgen it'll power the electric fuel pump.

 

Powers the fuel pump if the fuel pump relay fails.

On carbed cars with electric chokes, the switch is used to keep the choke from getting power when the engine is not running.