BB GM Heat Riser # 3940977
 

Need an NOS one .....

Re: BB GM Heat Riser # 3940977
 

Ed,

Did your part number supercede another number? I can't find your number in my GM books. I have a GM heat riser but it has another number stamped on it.

Re: BB GM Heat Riser # 3940977
 

if your looking for the heat valve on the passenger side I just bought 3 of them from the dealer. dealer cost is $39.83
#3969903

Re: BB GM Heat Riser # 3940977
 

I was informed today that the 903 is the only one avail. Im still reserching this - its for a 69 yenko camaro Feb built car. What im told the 903 is what is currently used for quite a while now.

As for the 977 part number - i was given this number as the correct one - so im not sure if its an old number or a mistake.

Re: BB GM Heat Riser # 3940977
 

MY 1972 PARTS BOOK SAYS 3969903 1967-1970396- 454 / SUP 3887033-3940977

Re: BB GM Heat Riser # 3940977
 

How do you tell which one you have? I have two saved for my resto. If I put them with the doughnut mount surface down on the table, one has the weight and spring on the left and the other has it on the right. The weight on that's on the left has p/n 3746844 cast into it. The other one looks new. Both picked up at swap meets 10-15 years ago.

Re: BB GM Heat Riser # 3940977
 

I have one and the exhaust manifolds that we took off my friends Chevelle back in 73 or 74 when we put headers on it. He was going to through em out so I keep them. The dates on the exhaust manifolds are K-7-9 October 7th 69. The heat riser only has a B34 on the balance arm. There looks like it might another number below that but I cant make it out. Is that the number on the bottom of the balance arm ? If it is I will try and make it out.

Re: BB GM Heat Riser # 3940977
 

I should have referenced how they sit. I put two holes toward me and one hole away from me. The doughnut surface is facing up. The rod that the flapper pivots on is about 3:30 and 9:30 (clock reference).

I found a third, weight on the right. One has the part number on the outside face of the weight, one has nothing.

The one with the weight on the left has B35 and 2442 cast on the inside face of the weight.

Re: BB GM Heat Riser # 3940977
 

Here is a picture of one that has the number 3746844 cast into the outside of the weight.

https://www.yenko.net/attachments/439364-donutup.jpg

This is donut side up.

Re: BB GM Heat Riser # 3940977
 

Here it is flat side up.

https://www.yenko.net/attachments/439367-flatup.jpg

The other side of the same part that has the casting number 3746844 on the outside of the weight. At least this will give you an idea if this is what you are looking for or not.