Hemi intake heat tubes

[ws23rt]

I have a stock manifold heating system and am thinking about blocking it off.  Mine is a 69 with clone carbs from Harms with electric choke.
My intent is to reduce the heat that gets to the carbs. If I block the riser open I wonder if that is enough. Is there enough exhaust movement when it is open to still heat the manifold? Should I block the tube to manifold connection as well?
What brings this up is the carbs seem to boil dry after running and it takes more engine cranking to fill them at start up than I am used to.
The heat riser seems to open as designed.
Next question about this is would the electric choke be miffed about this change and make me run too rich for too long?
My instinct says I am missing something because the system should work as designed.

[Fred]

 For me the solution was installing a fuel priming pump. No more problems with prolonged cranking.

[ws23rt]

I had not thought about that. It would answer my problem but not the question.
I had a 68 hemi RR that was a daily driver for several years and don't remember an issue. However that was back when we had gas for fuel.
So is ethanol a part of this question?

[Fred]

It could well be fuel.  I stay away from ethanol. I only use high octane 98 fuel. My carbi is a double pumper Proform. What carbi are you running?

[ws23rt]

My carbs are stock carter clone carbs.
Am on the lookout for originals but have seen prices as high as $5,000. Gulp---Not for my car.

[ws23rt]

For me the solution was installing a fuel priming pump. No more problems with prolonged cranking.

Have you blocked your exhaust from the intake?

[Fred]

For me the solution was installing a fuel priming pump. No more problems with prolonged cranking.

Have you blocked your exhaust from the intake?

I'm afraid I haven't got your setup.   I've got a hemi with  TTI headers and exhaust system.  

[ws23rt]

Well that does answer the question with your engine. Which is you do not have exhaust heating on your manifold.
But you still went to a priming pump. Was that because you had a manifold heat problem?

I think I am on a quest to find bottom line answers to problems that mopar didn't follow up on back in the day. And to hear from those that have a stock system that works ok or not.
I was waiting for a recall notice about this but 40 yrs and still waiting

[Fred]

No, I've never had a manifold heat problem. I installed the priming pump to get the fuel level up in the carbi to prevent prolonged cranking for when the car's been parked for long periods.

[maxwellwedge]

I have Hemi's with and without the tubes blocked and they all run fine. All with stock chokes.

[hemi68charger]

Why not block the tubes at the source, down on the exhaust manifold and pipe?