Yes, never assume anything...!!!! Ha I posted some questions up here a while ago about a vacuum issue I was having and didn't get one response. So being the persistent bastard I am I trudged on blindly. By the time I tracked down the little -temp vacuum switch- with the 3/8"npt not the 1/2"npt, I with the help of the napa guy came up with some crappy info. Now this is my first 67-72 chevy so its all been a learning experience. Anyways the P.O. switched the darn head on my 250 with a integral head off a 73-79 Nova. Just what I needed another boat anchor. Thats why there was no hook up for the manual choke.But no big deal, a $30 switch sets me off to get a 300 dollar head and I can return it to original. Oh and did we mention ......never assume anything