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Comment by Jason Edge on December 12, 2023 at 8:00pm

Neal, you may be correct on the choke heat tube spiral baffle. My thinking was it slowed the heated air down before it reaches the thermostatic coil in the choke cap, but it would also provide more metal surface area to heat the air as it entered. It might be a combination of controlling the rate of entry but also providing more total heat capacity. Regardless it was there to help control hot air passage to the choke thermostat.  I know the intake tubes can be installed without the spiral baffle but it affects the choke at least minimally.  Probably not enough to really worry about or even affect anything unless your car is being driving in the Arctic Tundra on a daily basis.

Comment by Neal Polan on December 12, 2023 at 4:38pm

Thanks for the quick response. I was under the assumption that the spiral mesh that’s inside the choke preheat tube was for the purpose of transferring as much heat from the tube as possible to the air that ends up being sucked in by the choke. Am I seeing that wrong

Comment by Jason Edge on December 12, 2023 at 4:00pm

Neal, I have actually seen a retrofitted tube or two off the exhaust manifold from the 58 parts cars. I think the last one was way back. If it is done right it should work. Of course it might take some tinkering with length, etc. to get the rate of heat flow correct ... or in the ball park to keep the choke butterfly closed at least long enough for engine to warm up a bit. Keep in mind there is a spiral metal baffle in the inner choke tube to limit the rate of heat flow. 

Comment by Neal Polan on December 12, 2023 at 3:11pm

Excellent article and video. Thanks. To bring hot air to the choke housing, what about using a 1/4" copper tube wrapped around the exhaust pipe (just past the flange) and then up to connect with the choke housing. I have done this when I was a mechanic for Ford, & then later when I had a restoration shop. This way you could keep the intake manifold cool, by using a new source of warm air. Has anybody tried that yet? I am planning to block off all 4 hot air sources, and center hot air runners and installing a heat riser bypass spacer. The stock Rochester does not have provision for electric choke like your Edelbrock.

Comment by Jason Edge on March 2, 2016 at 10:09pm

The butterfly is attached to a pivot rod. You can cut the butterfly from the pivot rod. This way you retain the outside thermostat spring and it will still look factory. This is what I did when I went back with original exhaust.

Comment by Jason Edge on November 15, 2015 at 8:06am

Dusty,

A lot of people cut the butter fly out and bypass that operation. Unless you live in very cold climate and often crank the car in very cold temps, it is really not needed. It's intent was of course to push fire hot exhaust gas across the center intake port to speed up the engine warm up. With that said, you will still need something there to take up the gap if running the original Y pipe since it will not mate up at the right angle if you remove it and try to bolt the LH Y pipe biscuit directly up to the exhaust manifold. You need a spacer there, or to cut out the butterfly of an existing heat riser, or remove the spring from one and wire it open. If running dual exhaust from the exhaust manifold then of course nothing is needed.