'67 BIG BLOCK HEAT RISER VALVE

[Rob A.]

I have a 2 1/2" heat riser valve that, when installed on my '67 big block, has the counterweight facing the rear of my car. It can't be installed with it facing the front. Does this mean the valve is not correct for my car, and if so, what car might this be correct for?

[Joe L.]

Re: '67 BIG BLOCK HEAT RISER VALVE

Rob-----

The heat riser valve can, theoretically, be installed in one of three positions and none of these result in the counterweight facing directly towards the front. My recollection is that the counterweight faces "forward left". If the valve is incorrect, though, I have no idea what application it's for.

The correct valve is GM #3887034 which is still available from GM. If you have that valve, you have the correct valve.

[Wayne P.]

Re: '67 BIG BLOCK HEAT RISER VALVE

Although available, I don't believe it matches the original. Unfortunately, I don't remember the difference.

[Dick W.]

Re: '67 BIG BLOCK HEAT RISER VALVE

Look in the archives. I believe that Dr. McCagh had a post on the differences.

[Brian J.]

Re: '67 BIG BLOCK HEAT RISER VALVE

The difference is the "boss" casting that holds the pin for the spring. Originals are the whole depth of the riser valve, the service replacement (still available from GM) is only half.
Brian

[Rob A.]

Re: '67 BIG BLOCK HEAT RISER VALVE

Brian,

The valve appears original, however, will only mount with the counterweight facing the rear/side of the car. I see in the full underneath shots in Nolan Adams book, that the weight faces forward, so I'll assume it's not original to a corvette.

[Brian J.]

Re: '67 BIG BLOCK HEAT RISER VALVE

Rob,
I understand your problem, I was just pointing out the differences between an original and a service replacement.
Brian

[Joe L.]

Re: '67 BIG BLOCK HEAT RISER VALVE

Wayne----

Yes, the current version of this piece is not exactly like the original. However, if one has a GM #3887034 it is guaranteed to be the FUNCTIONALLY correct piece for the Corvette application. In that case, any problem with installation has to do with the installer and is not related to having an incorrect part.