nox valve

hello all
1973 challenger 340 automatic
i dont know where the nox valve hoses go to can anybody help
bottom of valve states carb but where at the carb and the top of valve nipple i have know clue.
any pic would be great
thanks
sjm

steve maluk said:

hello all
1973 challenger 340 automatic
i dont know where the nox valve hoses go to can anybody help
bottom of valve states carb but where at the carb and the top of valve nipple i have know clue.
any pic would be great
thanks
sjm

Click to expand...

73 big block, not positive if 340 routes the same .

The OSAC (Orifice Spark Advance Control) valve was used in 1973 to help control NOx (oxides of nitrogen). It is in the path from the vacuum advance on the distributor to the ported vacuum port on the carburetor. For the 340 Thermo-Quad,it is on the front lower left at the base.

From the 1973 factory service manual for 318/340/360:


OSAC port on the Thermo-Quad carburetor base: