The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 55.2-59 Counter weighted rotation thingamajig in exhaust???

geezer#99 · 03-31-2020, 03:41 PM

Yes it’s a heat riser or heat diverter.
Deflects some hot exhaust on to the underside of the plenum on your intake. The plenum is that area on your intake right below the carb. The heat helps to keep the fuel vapor atomized. Cold fuel vapor will revert back to larger fuel droplets. You’ll get some lean misfires without it. The Chevy six takes a long time to heat up without it.
If you don’t mind a rough running misfiring motor until the motor gets up to temperature then remove it.
If your ambient temp is always above 10C you could remove it. Hotter air intake helps.

03-31-2020, 03:41 PM	#4
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,515	Re: Counter weighted rotation thingamajig in exhaust??? Yes it’s a heat riser or heat diverter. Deflects some hot exhaust on to the underside of the plenum on your intake. The plenum is that area on your intake right below the carb. The heat helps to keep the fuel vapor atomized. Cold fuel vapor will revert back to larger fuel droplets. You’ll get some lean misfires without it. The Chevy six takes a long time to heat up without it. If you don’t mind a rough running misfiring motor until the motor gets up to temperature then remove it. If your ambient temp is always above 10C you could remove it. Hotter air intake helps.