GM 250 CHEV L6 INTEGRAL MANIFOLD I.D. CHART - F# ON MANIFOLD TOP        
CARB A.I.R - SMOG VALVE COVER                      SMOG TUBES YEAR CASTING # PART #
1BBL NO 7" WIDE, W/AIR CMBR, DUAL RAIL 75-76 355795 CF2416
        370696  
1BBL NO 5" WIDE, SINGLE RAIL 77-78 377131 CF2410
1BBL YES 5" WIDE, SINGL, 6 SMOG HOLES 77-78 377131 CF2414
377133
        14002012 CF2417
2BBL YES 5 TUBE HOLES 79-86 3364 CF2415
        14015499  
2BBL YES 4 TUBE HOLES 3364 CF2412
        14015499  
                            GM 194, 230, 250, 292 CHEV L6 NON INTEGRAL MANIFOLD  
ALL 11/32 VALVE HEADS INTERCHANGE - SPEC. SMOG AND TEMP. SENSDER (SOME HEADS
SENDER IS LOCATED IN HEAD OF IN THERMOSTAT HOUSING) 292 C.I. L.P.G. + H.D. USE 3/8
EX. VALVE, EARLY = SENDER IN HOUSING, LATE = SENDER IN SIDE OR END OF HEAD