Real Deal - 1956 only heat riser valve

[Edward M.]

Just thought would share this with all of you.

This is an NOS 1956 only Corvette (all engines) and passenger car 2x4 bbl engines exhaust heat riser value assembly. The GM part number is 3731396.

Note the Markings on the upper side that says "TOP" and below that the letter "M". I believe the "M" refers to the manufacturer of this part.

Also note that the bottom side of the heat riser is flat. The exhaust pipe also had a flat flange on it.

The tapered exhaust pipe to exhaust manifold / heat riser started in 1957.

I found this gem sitting out on Ebay. The seller knew what it is, but I don't think they know how rare it is.

I have never seen an NOS one of these before.

[David B.]

Re: Real Deal - 1956 only heat riser valve

Sold an NOS one on Ebay a number of years ago. That might be the one. I thought most 56-57 owners knew the difference you explained. Hate to think I am showing my age by thinking it was common knowledge.

[Edward M.]

Re: Real Deal - 1956 only heat riser valve

I suspect that most 56 - 57 owners do know the difference. What I found was that some 56 owners did not know what a real 56 heat riser looked like.

I also found that the Tri-Five Classic Chevy people were totally in the dark on this.

[Sander B.]

Re: Real Deal - 1956 only heat riser valve

here is another one up for sale http://www.ebay.com/itm/NOS-1956-Che...hXo7OL&vxp=mtr