69 Z28 passenger exhaust manifold pic

[69Z28]

Hi guys, need some help, anybody have a stock factory style exhaust system using the factory exhaust manifolds still on their car?..Z28 or SS350 might or might not matter, but I'm gonna assume it doesn't.  I need a pic of the heat valve and it's orientation/clocking on the passenger side manifold.

[BULLITT65]

This is the best I have on hand, you can see the peg that the spring mounts to. Hopefully you gather enough from this to install yours. (The manifolds have never been off of the motor.)

[JohnZ]

Here's my '69Z.

[69Z28]

Both of those pics show me that this valve is different on both cars, or is it the way it's clocked? The valve I have, if installed, will actually be 180 out from Johns valve. If I install it with the flat gasket side facing the manifold outlet, which should be up, I think, then it definately will be opposite of Johns. Bullitts pic, from what little info is showing, leads me to believe that the valve I have is all wrong.

Here is a pic of what I have and you can see the difference. Doesn't even look close to me.  

[BULLITT65]

Hey Gary, let me start off by saying my exhaust system was replaced at one point so someone could have rotated my valve. But looking at your picture if you flip it over and look at John Z pic you would have it in the same position as his. For my car if you flipped it over and then turned it a 1/3 of a turn clockwise it would be how mine is installed.

So from what I see John and I have it facing the other way and John has the weight down, you rotate it 1/3 clockwise, and the weight would be up, like mine is (you just can't see it in the photo sorry).  If you look at the peg that the spring is retained by in my pics you may see what I am saying.

There might be someone on the CRG that has a V-8 Camaro with the original pipes and valve still installed on there car that may give us more insight. Maybe one of those original small block pace car guys could post a pic?

[69Z28]

I didn't have a valve before I bought the one in my pic. The seller said it came from a 70 Corvette, but I have no clue really. Are these valves made different from model to model and/or from Rams horn manifolds to log type manifolds? I just bought another valve  which says it is number 3746844 and not even sure it is correct. Here's a link to the one I just bought. I still don't think I'll have the correct one to install.

http://www.ebay.com/itm/vintage-chevy-exhaust-small-block-heat-riser-3746844-with-diamond-up-engraved-/310785661240?_trksid=p2047675.l2557&ssPageName=STRK%3AMEWNX%3AIT&nma=true&si=vRtriaDfWUccNfL9O0OoOVL9V3A%253D&orig_cvip=true&rt=nc

[Everett#2390]

In Post 3, the side shown mates with the manifold via a gasket.
The bevel side underneath, mates with the exhaust pipe donut.

[69Z28]

In Post 3, the side shown mates with the manifold via a gasket.
The bevel side underneath, mates with the exhaust pipe donut.

Yes that is correct but what I can't 'SEEM' to wrap around my head is if what I have is correct or not. The survivor 69 Impala I have has the same valve in my pic, post #3, with Rams horn manifolds, which appears to be different then the valve in Johns pic. The weight on mine as installed will be on the left as Johns is on the right. I guess what I'm trying to figure out is does it matter how it's clocked and a proper installation for 69 Z and/or small blocks? I think what we need are pics of original installations as stated by Bullitt to verify what is correct. I don't know what is correct.

[69Z28]

Hey Gary, let me start off by saying my exhaust system was replaced at one point so someone could have rotated my valve. But looking at your picture if you flip it over and look at John Z pic you would have it in the same position as his. For my car if you flipped it over and then turned it a 1/3 of a turn clockwise it would be how mine is installed.

So from what I see John and I have it facing the other way and John has the weight down, you rotate it 1/3 clockwise, and the weight would be up, like mine is (you just can't see it in the photo sorry).  If you look at the peg that the spring is retained by in my pics you may see what I am saying.

There might be someone on the CRG that has a V-8 Camaro with the original pipes and valve still installed on there car that may give us more insight. Maybe one of those original small block pace car guys could post a pic?

But you can't flip it over, that puts the flange/donut side facing up which isn't correct. If I install mine as it is shown in this pic here then the lever will be facing the rad support/front of car compared to what Johns pic shows facing the fender well. No matter how I orient this particular valve it will never be correct based on yours and Johns pic. Looking at my pic the wire spring will be up, I bet yours and Johns is underneath and cannot be clearly seen. I'm still thinking I have the wrong valve not to mention the one I just bought will be wrong too. How many variations can there be. Geeze.

[69Z28]

Here's the flange side of the one I just bought. Number on the lever is 3746844. Is this even a good number for the 69 small block? You can clearly see it's the same if you flip it flange side down. I have seen this number too, 7752901, but don't know much about it. One forum I found that on says correct for 69 Z28 but heck IDK.

[MyRed67]

I'm thinking if you install it with the Flange side up, it will not open properly.

[BULLITT65]

If you installed it just as it is pictured it would be in the same position as mine. Here is another pic
( again sorry that it cut off a bit, when I took the pic it was of the whole side of the motor)

[69Z28]

The heat valve isn't reversible so it won't work that way, the donut gasket/ flange side faces down towards the ground so it seals the head pipe to the heat valve. The flat side mates to the manifold outlet and has a flat gasket to seal any leaks at that connection. Can't seem to find any pics or maybe a diagram showing how this is set up in general terms. Went thru the 69 A.I.M. and haven't seen anything there either. Every body must be using headers on there cars. I would have thought there would be more replies. Anybody else have something to verify correctness?

[BULLITT65]

Well I am a little confused. Are the to valves you posted the same part or are they different? they both look like they have a bevel in each picture.

[69Z28]

Yes, this is confusing, and  both valves are identical. My reply #3 and #8 show the valve flat side up on the one sitting on my desk and the heat valve in my reply #9 is flange side up and is the valve I just bought and haven't received yet, and for what it's worth is identical to the one I already have. Without anything to go by it's going to be hard to verify if what I have is even a correct heat valve for the 69 Small block. Nothing to go by if there is no other participation from other members. Just need a good clear pic of this heat valve and it's orientation. I think what I have may be for the Rams Horn style exhaust manifolds like what's on my 69 350 Impala. IDK.