TH 350 questions

I just installed my newly remanufactured TH 350 behind a SBC 400...on the right side near the cooler fittings is some kind of a pressure switch with two blade connectors on it....what is this for ?....and lastly the vacuum modulator gets connected via a hose to which fitting on the carb ?...I'm using an early Quadrajet carb, 1967 vintage....does it in fact go to the carb or does it connect directly to manifold vacuum ?....Thanks...Mike S.

 

reverse light switch? The vacuum goes to the intake vacuum fitting behide the carb.

 

either reverse lights or nut safety switch???? constant vacuum, either location

 

Those were used back in the days of early emission control that altered timing advance depending on what gear the trans was in. The switch told the distributor when the transmission was in high gear. Hook your modulator straight to manifold vacuum.

Bob

 

Transmission Controlled Spark Advance (TCS). It's an emissions device.

 

You can remove the TCS switch and put a 1/8" pipe plug in it's place.

 

ok so I'll put the modulator hose to manifold vacuum...not ported vacuum...thanks,men !!

 

Connect the vacuum modulator directly to the manifold, if you can.

 

That switch was used in the early 1970's to cut off vacuum advance in 1st and 2nd gear for emissions control. There were different version of the system, it was used from 70-74, and they got more complicated each year - with temperature sensors, anti stall dash pots, deceleration throttle stop, time delay etc.