The spring on exhaust manifold is broken, where can I find a new one and id much of a job to install, thanks

Are you talking about the spring that controls the heat riser flap?

I assume so....cant think of any other spring.

Ours broke too.....seems that any repair kits still available are $150-$200.

The end tab that limits movement on one end of ours is what broke off.....so we tried to weld a tab onto it....failed.

The consensus seems to be that for a cold weather car especially the heat riser flapper is a required "keep".

We just decided to bite the bullet and get a whole new Dorman exhaust manifold.

Wish I had better news....

Why couldn't I just cut butterfly out. This is on an industrial slant six.
Thanks

Because the factory put it there for a reason?

Because then your engine will run poorly, producing less power and/or using more gasoline and washing oil off the cylinder walls. The valve is there for a reason, and (contrary to popular misunderstanding) it is not just for cold weather.

A repair kit used to be available for the heat control valve. The kit for the pre-'71 manifolds was discontinued decades ago, and the kit for the '71-up manifolds went away about 15 or 20 years ago. NOS examples are sometimes found, usually at eyewatering prices.

Aside from the spring problem, there's bound to be wear (slop) on the shaft and at the unbushed holes where the shaft passes through the manifold walls, and it's more than likely your manifold is warped.

Your best way forward here is going to be a new Dorman exhaust manifold, which will come with an all-new valve installed, with no slop at the (bushed, MUCH less seizure-prone) pass-through, no warp, etc. If you dig around you'll probably find a different-brand new manifold at a lower price. They're cheaper because they're significantly poorer quality. Options are:

• Buy a used one: spend less money, but you have to hope you get one that isn't warped, cracked, leaky, or otherwise faulty. Hope it stays that way.

• Buy a cheaper-than-Dorman new one: spend middle money, but you have to contend with poor casting quality and accuracy. Makes it a pain to install, too.

• Buy the Dorman new one: spend more money, but "done in one" and you can move on to thinking about things other than exhaust manifolds.

The new manifolds are all '73-'87 type. Bolts right onto any year engine, mates up with whatever intake manifold you want to use, etc. The difference is in the choke pocket, which in your particular case you only have to care about if you have an automatic choke on your industrial motor like the car/truck/van slants do, and even then, there are easy workarounds (put on the appropriate Electric choke kit and wind up with a better choke system anyway)

It is very much worth your while to get the good gaskets for the manifolds-to-head and intake-to-exhaust junctions.

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Too many people who were born on third base actually believe they've hit a triple.

I just went through this....it was tough to spend $250 for a new Dorman.....ouch......but as Dan said, if you believe the flap is needed (and I do, at least with all the emissions related stuff on my particular engine...I don't have one on my Barracuda's 318 that has headers and its fine though I need a 10 minute warm up period before driving it, ok by me) its the pnly game in town really. I saw one other brand but it was just as pricey....I never found a much cheaper alternative.

The bonus is that the Dorman product has an O2 sensor bung in it...so we can add an air fuel gauge EASILY if we want.

I just re-bent the broken end. Maybe the "calibration" was off, but it's a really old corroded piece, so : "what calibration?" Seems to work OK on our daily drivers.

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"Louise", a 1976 Dart Custom project, (now sadly reverted to being just an "organ donor" to our other project Darts.)