Hey, My 78 Malibu and El Camino both had 305 c.i with a TH200. I had a 78 Malibu four door with a V6 and a TH350. My 79 had a V6 TH350 also. The TH350 will have a vacuum line running from the module to the back of the intake and a TH 200 will not. GM also installed a TH250 in those car`s.