Heat riser question

[AASmedic]

I have a question about a heat riser valve. Were they installed on the Big Block engines only or did the 350's also have them? My research has led me to a dead end. I had a 72 Cheyenne C-10 many years ago that had one but i'm not sure if it was an add-on. At any rate, I have a 72 K20 and there is not one on it. The bolts are definitely long enough though. Any info would be helpful.

Thanks,
Kevin

[AASmedic]

Anyone?

[toolboxchev]

Post a pic please, the heat riser extends internally into the engine block and most of the exhaust flapper valves have been removed long ago.

The make noise and when stuck cause other issues.

I have a spacer block in mine, yet its on the wrong side due to utilizing a 327 exhaust manifold stolen off an old Chevy II or Nova.

Tell us more please!

[AASmedic]

This is the valve I am referring to. As I remember it, it was on the output of the passenger side manifold. My K20 has long manifold bolts as if it was originally there but not sure if it is supposed to be.

[Stocker]

When I bought my '72 K20 (with 350 engine) in 1977, everything appeared to be bone stock and original.... and it had a heat riser valve like the pic you posted above. Can't recall if it got stuck or got noisy but I eventually replaced it years later, then removed the replacement after a short time. Been running with just a spacer for many years and have not missed having a heat riser. You're right, it was at the bottom of the passenger side manifold.

[AASmedic]

Originally Posted by Stocker

When I bought my '72 K20 (with 350 engine) in 1977, everything appeared to be bone stock and original.... and it had a heat riser valve like the pic you posted above. Can't recall if it got stuck or got noisy but I eventually replaced it years later, then removed the replacement after a short time. Been running with just a spacer for many years and have not missed having a heat riser. You're right, it was at the bottom of the passenger side manifold.

Thanks Mike. I thought that was the case. I am betting that mine was removed at some point as well. I dont see the need for it at this point but I do believe that I need a new set of ram horns. I think mine are cracked.

[Stocker]

Ouch -- been there & done that too, a very long time ago. Drivers side cracked, all I could find locally was one with A.I.R. holes. My truck was never equipped with a smog pump, and now that manifold has plugs in those holes.

Come to think of it, besides having cracked heads years ago, I also had a cracked intake manifold. Replaced it with an Edelbrock 2101 iirc.

[AASmedic]

Lol...fortunately I dont have those issues but would like to get rid of the leak. I will have to search and see whats out there.