plus, there are different tubes and therefore different sticks. The base tube barely meets the top of the trough in the valley of the exhaust manifold. Then there are the tubes with an extension tube attached (about 3 or 4 inches with a slight curve this attaches with a sheet metal screw to the manifold heat shield at the top and requires a longer stick.
I'll get you the part number from the dipstick of my '72 350 this afternoon so you at least know what was originally used.
I have one here that's in excellent condition for the Tube Style. Pretty sure this is for a 350 but you may want to double check! GM Part Number on it is 1234632 It also has a "White Tip" if that helps . . . . (Original GM) I'll be listing this later today. $20 plus shipping. (Basically same price as the repops)
