1966 383 exhaust manifold heat riser delete

[Bryon Mason]

My engine is currently at the machine shop and while I have it tore down I was wondering what is the best way to delete heat riser from the exhaust manifold. I've read that they really aren't necessary and unfortunately mines missing all the springs.

 

[CBODY67]

If it's stuck, just deform the flapper and remove it, leaving the shaft and external remains intact. If it will still move, then remove the shaft, remove the flapper, and reinsert the shaft and weight with nobody being the wiser.

There is ONE way they are needed. IF exhaust is not directed to the heat crossover of the intake manifold, the automatic choke coil will only heat up as heat migrates from the cylinder heads into the intake manifold. Which can delay choke opening a bit. With an elec choke carb, no need for that heat to happen quickly, relating to the choke openning quickly.

BUT with no heat directed specifically to the heat crossover, even with an electric choke carb, a bit of extra care to keep things running in cold weather might be needed. Even with an aluminum intake manifold. Which might mean you might need to pay attention and tweak the automatic choke setting a bit for best results. Using the FSM settings as a starting point. Which CAN depend upon your area's temperatures into the colder months of the year. Which might also mean paying attention to the ignition system's capabilities, too!

Your judgment call,
CBODY67

 

[Bryon Mason]

If it's stuck, just deform the flapper and remove it, leaving the shaft and external remains intact. If it will still move, then remove the shaft, remove the flapper, and reinsert the shaft and weight with nobody being the wiser.

There is ONE way they are needed. IF exhaust is not directed to the heat crossover of the intake manifold, the automatic choke coil will only heat up as heat migrates from the cylinder heads into the intake manifold. Which can delay choke opening a bit. With an elec choke carb, no need for that heat to happen quickly, relating to the choke openning quickly.

BUT with no heat directed specifically to the heat crossover, even with an electric choke carb, a bit of extra care to keep things running in cold weather might be needed. Even with an aluminum intake manifold. Which might mean you might need to pay attention and tweak the automatic choke setting a bit for best results. Using the FSM settings as a starting point. Which CAN depend upon your area's temperatures into the colder months of the year. Which might also mean paying attention to the ignition system's capabilities, too!

Your judgment call,
CBODY67

It moves freely, not stuck at all, im in Florida so cold weather really isn't an issue.

 

[LocuMob]

You can cut it and put a bolt in its place. Or just leave it, it won't affect performance any. I leave them when they move freely.

 

[Bryon Mason]

You can cut it and put a bolt in its place. Or just leave it, it won't affect performance any. I leave them when they move freely.

Thanks, that was my concern , although it moves freely i was worried somehow it would affect performance by not having all the springs in place.

 

[LocuMob]

Thanks, that was my concern , although it moves freely i was worried somehow it would affect performance by not having all the springs in place.

The exhaust pressure should keep it open. Only when they are stick closed, do I worry.