The thingy is a heat-riser valve. It's on my '73, I don't know if they went to something else in '74 or if the PO just threw it away (sunny California). I really never quite understood it. In Use: 70 1210 4x4 TE, 73 1210 WM Project (2nd time) 67 1000B PU Parts: 67 1000B TA 68 1100 4x4 TA 72 1010 TA