I just pulled my intake/exhaust manifolds to install an Offy 4 barrel and noticed that the heat riser valve is welded shut on the exhaust manifold.
Is this an issue?
I am installing a 390 holley with an electric choke.

Thanks,
moparstac

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66 A100 Pickup - 225 Sloper
64 Barracuda 273

it is only an issue during cold starts, on really cold days.
DD

Moparstac, I have a '72 Scamp 225 Offe 4bbl with Holley 390 based in Southern California. Not sure where you are but the weather here is quite mild. When I bought the car the heat riser was missing the bi metal spring that opens it when hot and the damper was stuck open with another spring. I read a lot of info and the best info stated that Ma Mopar rarely did extra work if it wasn’t needed. I even saw guys that ran hot water through the intake because they were running headers. Turns out the atomization of the air fuel mixture is critical to performance and the heated intake plays a big part in that. My car was pretty hard to start even on warmer days. Because I’m running the Holley I lost the heated air manifold that runs to the air cleaner so I decided to get the heat riser working. I managed to find a spring on line with a different damper but the spring was correct. Setting up the damper has really made the difference in cold starts. If you can save the damper I would give it a try and see if it improves your performance.

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'64 Valiant Conv V8
'72 Scamp /6 4bbl
'79 Adventurer SE

Define "shut"...

The shaft is welded, not the flapper. It is not completely sealed off around the flapper. I am not sure how much more closed it could be, though.
I am sure that if it worked it would be better, but is it a big deal.

StephenShawScamp,
Is your 390 an electric choke version?

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66 A100 Pickup - 225 Sloper
64 Barracuda 273

Yes on the electric choke 390. I took off a chokeless version and this was a huge improvement on starting.

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'64 Valiant Conv V8
'72 Scamp /6 4bbl
'79 Adventurer SE