BB GM Heat Riser # 3940977

**Donnie** · #1 01-13-2010, 05:24 AM

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

**enio45** · #2 01-13-2010, 07:03 AM

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.

**BARRY** · #3 01-13-2010, 08:40 PM

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

68SSCamaro · #4 01-13-2010, 08:58 PM

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.

68SSCamaro · #5 01-17-2010, 08:21 AM

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.

**John Brown** · #6 01-17-2010, 09:29 AM

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

This is donut side up.

**John Brown** · #7 01-17-2010, 09:31 AM

Here it is flat side up.

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.

**GaryC** · #8 11-15-2013, 02:26 AM

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: John Brown</div><div class="ubbcode-body">Here is a picture of one that has the number 3746844 cast into the outside of the weight.

This is donut side up. </div></div>

I'm re-opening this thread, I have 2 of these heat riser valves and have no idea what they go to. They both have 3746844 cast into the side of the lever block. Anybody ever figure out what these are supposed to go on?

my69rat · #9 01-16-2010, 01:42 AM

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.

Dedicated to the Promotion and Preservation of American Muscle Cars, Dealer built Supercars and COPO cars.