Exhaust Heat Riser 327/300hp

[Terence M.]

I am new to using the forum but here goes.
I am looking to get a picture or advise on how the heat riser is orientated on a the passenger side exhaust pipe on a 1967 327/300hp corvette.
I have been told mine is incorrect.
Terry

[Scott S.]

Re: Exhaust Heat Riser 327/300hp

I am new to using the forum but here goes.
I am looking to get a picture or advise on how the heat riser is orientated on a the passenger side exhaust pipe on a 1967 327/300hp corvette.
I have been told mine is incorrect.
Terry

Terry,

Check this Thread: C2:67 Heat Riser Valve

The pictures are no longer there, but it still may be helpful. The drawing in the 1967 Assembly Manual is on UPC 6-C1. The small block heat riser section in the 1967 Judging Guide is on page 83.

Hopefully someone will post a few pictures, that usually helps more than a thousand words

[Terence M.]

Re: Exhaust Heat Riser 327/300hp

I checked and read the Assembly Manual and numerous cataloges.
C2 67 Heat Riser Thread helpful but a picture would sure help.
I was told it was upside down so I took it off yesterday to flip it over but once I had it off I could see the ball and socket like fitting that would have to fit together between the exhaust pipe and Heat Riser. So I put it back the way I had it. With only three bolts on exhaust manifold it can only fit 3 differant ways. I have it facing firewall now.
Thanks for the reply!
Terry
PS How do I add a picture?

[Joe R.]

Re: Exhaust Heat Riser 327/300hp

Terry
PS How do I add a picture?

Terry,

Scroll down to "how do I post a picture?"

https://www.forums.ncrs.org/faq.php?faq=vb_read_and_post&uid=8018#faq_photos

Joe

[Scott S.]

Re: Exhaust Heat Riser 327/300hp

I checked and read the Assembly Manual and numerous cataloges.
C2 67 Heat Riser Thread helpful but a picture would sure help.

My car is completely disassembled at the moment. This is the best picture I can find, before we took everything apart (see below). I don't know for sure if that's how it was from the factory though, so if the example in my picture is incorrect, someone please say so.

PS How do I add a picture?

Here is an explanation that I have posted previously, there may be other (better) ways to do it, but this works:


"There are a couple ways to attach pictures. If you want to upload them to the forum so they appear as thumbnails (the way mine did above) this is the process.

1. On the screen where you normally type in your posts, scroll down below the "Submit Reply" button until you see the "Manage Attachments" button. Click on the "Manage Attachments".

2. To upload a picture file from your computer, click "Browse" in the "Manage Attachments" pop-up box, then search through your files until you find the picture you want to upload.

3. Double-click on the picture you want, which should automatically insert the File Path in the correct space of the "Manage Attachments" pop-up box.

4. Click "Upload", and wait about 30 seconds or longer, depending on the speed of your Internet connection, until the pop-up box shows that the picture file has been accepted.

I think that's it. If you click "Preview Post", you should be able to see whether your picture loaded properly."

[Joe L.]

Re: Exhaust Heat Riser 327/300hp

I checked and read the Assembly Manual and numerous cataloges.
C2 67 Heat Riser Thread helpful but a picture would sure help.
I was told it was upside down so I took it off yesterday to flip it over but once I had it off I could see the ball and socket like fitting that would have to fit together between the exhaust pipe and Heat Riser. So I put it back the way I had it. With only three bolts on exhaust manifold it can only fit 3 differant ways. I have it facing firewall now.
Thanks for the reply!
Terry
PS How do I add a picture?

Terry-----


The side of the heat riser with the large chamfer (i.e. beveled surface) around the bore goes DOWN. The chamfer mates to the exhaust packing ("donut" gasket).

The counterweight should be oriented towards the firewall.

[Gerard F.]

Re: Exhaust Heat Riser 327/300hp

Terry,

Here's a picture of my 67/327/300 heat riser refinished:



This picture is right side up, with the bevel for the donut on the bottom.

As I understand, the counterweight should be on the firewall side of the exhaust pipe with the weight pointed outboard to the passenger side. The shaft that holds the counterweight points to the firewall.

The weight goes down to open the valve.

Have I got it right, Joe? A lobster to you, if I don't.

[John H.]

Re: Exhaust Heat Riser 327/300hp

As I understand, the counterweight should be on the firewall side of the exhaust pipe with the weight pointed outboard to the passenger side. The shaft that holds the counterweight points to the firewall.

The weight goes down to open the valve.

Jerry -

That's correct - see photo below.

[Terence M.]

Re: Exhaust Heat Riser 327/300hp

Thank You all!
Of coarse mine is a little different:
I have it installed with camfer down but mine has no donut, my exhaust pipe is a ball fitting into the socket on heat riser.
So it is exhaust pipe to heat riser to small flat gasket to manifold
My weight is pointing up not sideways.
How would I tell if heat riser is original.
Thanks again!
Terry

[Gerard F.]

Re: Exhaust Heat Riser 327/300hp

Thank You all!
Of coarse mine is a little different:
I have it installed with camfer down but mine has no donut, my exhaust pipe is a ball fitting into the socket on heat riser.
So it is exhaust pipe to heat riser to small flat gasket to manifold
My weight is pointing up not sideways.
How would I tell if heat riser is original.
Thanks again!
Terry

Terry,

There is a date code and and number on the side of the weight:



Note sure what the number is, as it doesn't match the part number in the 67 AIM for my late 67. I would think the B 7 is February 67 for my late June car. I'm sure this is original to my car.

The 67 AIM shows a part number of 3887024 for the base 67 and 3746838 prior to a 6-14-66 change. But who knows what happened in late June near the end of production.

[Terence M.]

Re: Exhaust Heat Riser 327/300hp

Terry,

There is a date code and and number on the side of the weight:



Note sure what the number is, as it doesn't match the part number in the 67 AIM for my late 67. I would think the B 7 is February 67 for my late June car. I'm sure this is original to my car.

The 67 AIM shows a part number of 3887024 for the base 67 and 3746838 prior to a 6-14-66 change. But who knows what happened in late June near the end of production.

My car is a May 1967 build.
The number on part is 3748844
with linked diamonds above the number and 11 below.
My number is cast into the broad side of weight.
Thanks!
Terry

[Joe L.]

Re: Exhaust Heat Riser 327/300hp

Thank You all!
Of coarse mine is a little different:
I have it installed with camfer down but mine has no donut, my exhaust pipe is a ball fitting into the socket on heat riser.
So it is exhaust pipe to heat riser to small flat gasket to manifold
My weight is pointing up not sideways.
How would I tell if heat riser is original.
Thanks again!
Terry

Terry-----


If you have a "ball socket" on the forward pipe, that's not an original configuration. I have no idea what kind of forward pipe you have, but it's not GM and not even like any aftermarket piece I've ever seen.

The order of assembly of the various parts is as you mention.

[Joe L.]

Re: Exhaust Heat Riser 327/300hp

My car is a May 1967 build.
The number on part is 3748844
with linked diamonds above the number and 11 below.
My number is cast into the broad side of weight.
Thanks!
Terry

Terry------


The 4 digit derivative number on Jerry's weight as well as the full 7 digit number on your weight represent the part number of the weight and not the part number of the complete heat riser assembly. The weight was never available separately so the part number is strictly an internal GM number.

Given that you have this number on the weight strongly implies that the heat riser is original. Of course, it could also be an early SERVICE piece which would have been the same as PRODUCTION.

[Terence M.]

Re: Exhaust Heat Riser 327/300hp

I now believe it is all after market.
Thanks for all the help!
Terry

[David L.]

Re: Exhaust Heat Riser 327/300hp

Terry,

There is a date code and and number on the side of the weight:

Note sure what the number is, as it doesn't match the part number in the 67 AIM for my late 67. I would think the B 7 is February 67 for my late June car. I'm sure this is original to my car.

The 67 AIM shows a part number of 3887024 for the base 67 and 3746838 prior to a 6-14-66 change. But who knows what happened in late June near the end of production.

Jerry,

The part number change from 3746838 to 3887024 was July 1966 as Per Chevrolet Parts History for service parts which is very close to the assembly manual date change of 6-14-66.

I agree with Joe that the "6844" and "3746844" (Terry's) are casting numbers (and possibly part numbers) for only the weight.

I do not BELIEVE that your "B 7" is a date code and this is why. The original heat riser on my 1970 Camaro SS350 RH exhaust manifold (Casting # "3973432" and date code "E 29 0" or May 29, 1970) has a casting number "B 13" and "9428" on the weight. The GM part number for the heat riser in the 1970 Camaro AIM as well as in my 1970 Chevrolet Parts Catalog is 3887023. This manifold is NOT the "rams head" type so the heat riser is different.

The 1970 Chevrolet passenger car lists GM # 3887024 as the heat riser in the AIM which is the same part # as the 1967 Corvette because both cars use the "ram head" type of exhaust manifolds.

I now have another part to research. The "B 7" and "B 13" might be mold numbers.

Dave