demonkey36

I'm switching my 305 TBI out for a '74 350 Carb and I had some questions about the sensors. I obviously want to be able to use my existing wiring harness for the sensors, but when I go to move the sensors from the 305 to the 350, they are the wrong thread size. What should I do?

Also, which sensors do I absolutely need, and which can I forget about (since the induction is changed), and any pictures of each category would be greatly appreciated.

RB83L69

I assume you're talking about the ones that go in the heads.

You need this. It's a 3/8" - 1/2" pipe bushing. Available at hardware stores everwhere.

demonkey36

Any advice on which ones I need to move and which ones I won't need, and pictures of them or their positions on the block?

RB83L69

That depends on the car you're putting all this into.

You'll definitely need the one in the left head; that's the temp gauge sender.

You'll need the one in the right head if the car has an electric fan; that one is the fan switch.

You'll need a knock sensor, which goes in the pass side coolant drain hole.

You'll need a coolant temp sensor fot the ECM, which goes in the water outlet.

You'll need a MAP sensor and an ESC module, both of which go on the firewall between the brake booster and the fender. If the car has an electric fan, you'll need the fan relay and its wiring, which go in the same area.

And of course you'll need all the carb parts including the TPS and MCS and the choke wire and so on, and the EFE control valve, the canister pourge valve, the EGR valve and its control solenoid, and misc other goodies.

demonkey36

Well the computer's not staying...so I don't need a knock sensor and some other stuff, right?

demonkey36

here are the sensors i have questions about...

#1


#2


#3


#4


any others that a carbed 350 with no computer would need would be awesome, along with any pictures.

And I'm wiring up the Hayden 3652 fan switch...so I don't need the old one.

demonkey36

Anyone?

RB83L69

#1 is knock sensor.... you don't need that.

#2 is coolant temp sensor... not needed.

#3 is your temp gauge sending unit.... your call

#4 is the fan switch.... put your Hayden one in that same spot and use the factory wiring

demonkey36

Why is there a coolant temp sensor if you already have a temp gauge sending unit?

RB83L69

for the ECM