Having some 340 manifolds Jet Hot coated and do I really need to keep the heat riser assembly? It's not a concours car, so originality doesn't matter. If I ditch it, how do I get the flapper out? Cut grind it out with a dremel?

If you drive the car at all in cold weather you'll wish you kept it.

They are awesome to find intact.

Finding a manifold with one already removed may be easy if you offer yours up as a trade?

Someone out there has one with it deleted & they wished it had not been.

Earlier year manifolds: keep intact. Later: remove. They will rather if bushings are worn. Mainly stainless, so dremel may be a struggle.

I wanted to keep mine functional, although some parts were missing, so I had to order the rebuild kit anyway.

I got my manifolds jet hot coated, but sent in with the old bushings in place and I swapped them out with the ones in the kit after coating. I did make sure the old bushings were able to come out with no issues before sending in, to make it easier when the time came to drive them out. To get the old shaft off you either cut the shaft in two spots and remove the shaft in pieces or grind down the flapper where it is held on the shaft so you can slide out. Sliding out is a little more tricky as any burrs will get caught on the bushing as it comes out. More grinding or cleaning up is needed to get out.

To reinstall you need to tack weld the flapper back in place on the shaft, in the proper position. This is probably the most tricky part, clocking the shaft and flapper correctly. Lucky the welds are not visible, as my skills are not so great. As long as they hold, its fine. Take good photos before tearing apart, so you know what you are looking for.

Had mine removed, but retained the stock look from the outside. The shop that did the coating removed it for me so I can't comment on exactly how to do it.
Never gets cold enough here to worry about anything like that.

With todays fuels I'd recommend removing the butterfly at a minimum. Any heat that can be eliminated from the intake manifold area is a positive IMO. I have been removing them for years with no ill effects

Well I don't foresee driving this car in cold weather ; say below 60, so I think I may see if I can get the butterfly out and keep the remaining parts in place just for looks.
I read above where If I remove and replace with a repop heat rsier kit, I have to have some welding done? I'm not up for that as I've never done it. But thank you all for the replies.

Those look awesome!

I recall wiring mine open on a Road Runner back in the day, wasn't very visible.
That way, if I ever needed it in the future it was there.
Easier with the lever style than the round style, probably.

Steve,I saved all my extra pieces !

I tossed mine when I redid my manifolds. I kept the counterweight installed for a factory look. I'm surprised how quiet the engine compartment is without the annoying heat riser rattle. That noisy riser drove me crazy every time I drove the car when I was younger. I even replaced the original with a NOS unit back in 1979. I ditched mine and I'm sure that I'll never miss it.

Think my mind is made up, the flapper is gonna be taken out and the rest left in place. I'll see if I can have a neighbor possibly place a small tack on the counterweight so it's not spinning around an rattling.

Yeah, Bill, I do the same thing with anything I remove, even if it's crap and I've installed a better one.
If I sell a car, the buyer sometimes gets a trunk full of boxes, but I still have boxes of leftovers from at least a decade ago.
Got a big dump run coming up one of these days!
I just recalled a 50-year-old memory of the flapper rattling on Dad's '66 Sport Fury; had to be the 1st time I ever saw one wired open.