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It's on the passenger side exhaust manifold. Looks like some kind of open/close valve.
Heat riser. Closed when engine is cold to force hot exhaust through the intake manifold under the carburetor to run better and warm up quicker on those cold mornings. Most likely not needed in SW Florida. LOL.
I see your engine block is turquoise. What model and year is your car?
72 GTX RR 440 4spd 4bbl
I wired mine full open and rendered it inop on my first Road Runner back in '69. Thankfully it had been removed in my current Road Runner before I purchased it. It is pretty much an early (and poor) attempt at emission control.
It has zero to do with emissions.
It's function is to heat the underside of the intake manifold for better running when the car is cold.
And by "better running when the car is cold", emissions are reduced by getting it up to operating temp quicker. Right?
Probably, but it's not part of the emissions package and something that was used for years before emission standards were even thought of.
It dose get pretty cold here in the winter. Not as cold as up north but we do get into freezing here. Have seen it 27 degree here and it was below 32 for two day's. Being in central Fl. So that being said will rebuild my heat riser for those cold morning's. Getting older suck's will need a heater in the car for warming me up. LOL.
I here ya Russ my heater works good when not moving I need to replace the fresh air vent gaskets or like I do now use rags over the vents
Yep fixed mine welded cover's over them. Figure the vent window's will give me enough fresh air. With the added vintage air and heat should be fine. Found one heat riser repair kit for the 383. Don't forget that you can find something's not listed for Roadrunners but the same thing's where used on pick up truck's and Van's. That is how I found the striker plate for the door latch. Mine had a grove worn in it both sides. They look grate brand new always dose's.
it is smog related it’s the heat riser for cleaner faster warm ups in California if it is missing the vec fails smog. you would mark as modified.
HEAT RISER VALVE = TOTAL CRAP!!! These damn things always wind up corroding and getting stuck, usually in the closed position causing burnt valves or worse! They also restrict exhaust flow (even when open) which reduces horsepower. And I'm assuming that since you are a Mopar fan you like horsepower ;))
This is the FIRST thing I remove from any car that has one. It's not too hard to remove it, just drop your head pipe and remove the exhaust manifold for access. I removed it from each of the 4 road Runners I have owned, even back in 1970 on my brand new RR. Even back then everybody knew to get rid of those damn things before they damage your engine.
For maximum exhaust flow efficiency out of a stock manifold, it's best to remove the whole thing including the shaft the flapper valve rides on. Then you can plug the holes (from the outside) with a short oversized bolt or have a welder fill it and and grind flat. Lots of options how to do this just make sure you get rid of that damn valve.
Note: When you remove the exhaust manifold take a look inside it. I'll bet it has carbon build up from restricted flow.
Good time to clean it out.
Get some good headers. That will eliminate it and it will sound and look nicer. That's what I did anyway.