I'm planning to take the 352 that came with my '66 F250 back to near original and have a question about the exhaust control valve that goes between the manifold and the exhaust pipe. I've secured both passenger and driver side used manifolds (on eBay) and wonder if I need to also get an exhaust control valve too? What are the pros and cons of running without (or with) a valve? Mine will not be a show truck, so absolute originality is not a priority. Thx for the input. Jeff

 

Dose the manifold that you got off e-bay need the heat-riser? Look at the manifold, where the pipe hooks on and see if it has a tappered seat or a flat set. Flat seat is where you will need a heat-riser valve.

 

Jeff, that heat riser valve is designed to heat the engine more quickly. It works by directing exhaust from the driver's side over to the passenger side through a passage in the intake manifold. Once the thermostatic spring heats up, the valve opens.
Since you live in Canada, you may want to consider keeping it.
If the intake is replaced with one which does not have that passage (such as some after market ones, or possibly some other factory ones), then the valve is of no value.
The correct driver's side exhaust manifold is machined flat at the outlet, to mate with the flat upper surface of the heat riser valve. The bottom of the heat riser valve is machined to accept the exhaust pipe doughnut.

The later engines (after '67 or '68 I believe - someone else can correct me here I hope) quit using them. The driver's side manifold was re-designed to accept the doughnut directly.
This detail is important because it afffects the length of the exhaust pipe on the driver's side; the driver's side exhaust pipe was lengthened accordingly.

You have a couple of options. If you want to use the later exhaust manifold with a single exhaust pipe system, you can get the cross-over pipe from Auto Zone or Advance, by requesting the cross-over pipe parts (2 pieces) from a '76 F-150 with a 390. It will mate to your later driver's side manifold with the correct length, and you can splice it into your regular system.

If you have a dual exhaust, you may find it possible to simply extend the driver's side pipe upwards by a few inches, or, you can remove the butterfly from the valve, and use it on the correct manifold.

Of course, if your existing manifold and exhaust system doesn't currently use the heat riser, and you decide you don't need the heat riser, you don't have to put it in.

 

Banjopicker66: Thx for the reply. My 352 came without exhaust manifolds as it was replaced, by the sons of the original owner, with a 390 that had after market headers.(They threw in the 352 as it was cluttering Dads basement) So I don't know the OEM set-up for my 352. The e.manifolds I acquired are the tapered type requiring the direct exhaust pipe and donut connection. I'll have to have new pipes made, so the extra length will be done then.
However, your reply brought another question to mind. How do I figure out if the intake manifold is the one that has the passage for the exhaust gases to warm a cold engine? Then if I'm able to determine that, will the 352 performance suffer (or incur engine damage) if I fit it with later, non heat-riser e. manifolds and no heat riser valve?

 

Jeff, the only way I know for sure to see if the intake has the crossover is to remove it and check for the passage way. Most of them do, by the way.
If you do not use the heat riser valve, it won't matter if you have the crossover or not. It helps warm the engine up when cold, that's all.
And, perfomance and engine life will not be affected if you use the early or late exhaust manifolds. Same thing for intakes, it won't matter if the intake has the crossover passage (or not) if you do not use the valve. Or if you use the heat riser or not.
Except, of course, that it may take longer to heat up in cold weather if you don't use the valve, or if you use the valve but do not have the crossover passage.
Having said that, if the intake on your 352 is original, it has the crossover.
I still have my heat riser valve, and like it, but I like the traditional things better.

I'm curious, though, why replace the 390? It is a good engine, with more power than the 352. Gets the same mileage, too.
Why put the 352 back in?

Hope this helps!

 

Banjopicker66: Thx, again. the 390 is already out as I'm doing a cab-off clean-up. I'm interested in restoring the f250 to near original and not so interested in power. I have a keen interest in seeing old pieces of equipment brought back to original (or near-original). Like you, interested in the traditional. Thx again for the input to my dilemma. Jeff
PS I'll check out Slick60's as well.

 

Since you want to restore it too orginal condition, keep the existing system. Personally I run a rebuilt 352FE with headers and dual exhaust. In cold weather it runs the same as it did when it had the exhaust valve. I would say for a resoter, use the OE stuff. But that thing is unnessary in my view and have yet to see its advanatage. Dont forget that Ford dumped the valve in 68. Good luck on the truck. Sometimes I kick myself for modifiying my truck for more power and convinece, there is nothing like an all orgianl truck. But whats done is done.

 

Jeff, I too would keep the valve...Fords are notoriously cold blooded in the northern areas anyway....Im in Wa state...If you want a valve..I do have an NOS one if you are in need of one...Let me know....bp...the early 67's had the 352 and thus the heat riser valve....I know of where one is...last I saw it had both m/folds on it too....if you want the correct ones Jeff...give a holler and I'll go see if they are there...will be going there today myself....

Let me know....cs65

 

Camperspecial : Thx for the input. I'm interested in the manifold and valve from the wreck you mentioned. Let me know if available. Jeff