I recently bought an '86 k5 with 305. In order to register in MD. one needs a "safety inspection". New to the area and didn't realize what all they inspected.
The station is telling me I need a valve that's in the y pipe right below the manifold. I'm assuming that this is the heat riser valve but I saw a post that suggested there may be something called an exahust restrictor.
I can find the heat riser to fit the same year truck but for a 350CID. I know that the 305 is built on the same block but does anybody know if the part is interchangeable?..The only place I've found it is LMC Trucking and they're over $300. Really don't want to play they shipping back and forth game if it doesn't fit.

Any help greatly appreciated.

 

Should be the same exhaust manifolds and all. You should be good to go. I am surprised that they are requiring this though... Must be due to the age, even though it is 23 years old now.

 

Thanks for the input.

 

BTW Rocks has the same part for under $100. I was just gonna cut the shaft out of the old valve and weld the hole closed. It would at least "look" like the valve was there. But I guess for the price might as well put it in. Being as I appear to be stuck in the great white north now might as well have a truck that warms up quickly.

 

Did the 1986's come with a heat riser or vacuum operated EFE valve. I have an EFE valve on mine and safety wired it in the open position.

 

It actually is a vacuum operated EFE valve but from what I can gather it does the same thing.
As far as wiring it open when I got this one of the butterfly was separated from the shaft driven by the vacuum valve. So it didn't work anyway. If it was leaking so bad around that shaft I would have just removed the butterfly and reinstalled.

 

Finally put the new heat riser/ EFE valve in. That and resealing all the joints on the exhaust made a huge difference in how quick the engine got to operating temp. Pain in the "you know what" getting it in what the home-built, at least that's what it looks like, exhaust.

Sure feels like sealing the exhaust leaks, yes EVERY joint, and re-installing new gaskets at the start of the "Y" pipe gives it a little more at take-off.