I've got the original carb (yup, the throttle shaft is pretty loose) on the 455, but when I got it several hoses were missing or rotted off. I have never been able to find a vacuum diagram for all of the fittings on the carb. I'm specifically confused about a port on the front face of the carb. The port is on the passenger side of the front face, quite high up the carb. I've found a partial diagram for the engine, but it doesn't show this port. For the last few years it's been hooked up to vacuum advance, but I see from the partial diagram I have that vacuum advance should go elsewhere. Can anyone shed some light on this port? Thanks in advance, and happy sailing! The diagram I found is from a google search for "1970 455 vacuum diagram," I haven't got enough posts yet to put in the link...
one goes from the carb to the dist and the other one goes from the carb to the temp sensor that controls the vacume doors in the air cleaner assembly....to give the engine warm air or cold air....
Thanks for the reply Doc. I've got those two figured out from the diagram I found with google (wish I could post links already!), but there's a third port on the pass side of the front face of my carb, in addition to the two you've mentioned, which I have now hooked up properly. Hmmm... still a mystery...
Looking again at the carb, I noted that there's a broken vacuum pot that restricts/retards/locks out the secondaries under vacuum. I surmise that the broken/missing pot is where the “extra” vacuum fitting on the Pass front face of the carb goes. Neither that pot nor the associated port are not shown in the one diagram I've found. <style type="text/css">p { margin-bottom: 0.21cm; }</style>
If it were a early 70's I could help out. Not sure the vaccuum lines are the same though from '70 to '73
That would be the port; - it's supposed to be a buffer to restrict the secondaries from snapping open too fast. I think those dash-pots are still available new, if not, try ripping one off of any GM product from '69-75, -preferably from a salvage yard.:laugh:
Thanks for helping out folks. For now, I've plugged it off until I get a new pot. I wonder if it'll drive any different now that the distributor is hooked up as it should be?
