390 loading up when hot

[390owner]

My newly rebuilt 390 want to load up and not idle when the weather is hot like it has been here in Arkansas the last week. It has a 600 edelbrock on a stock intake. I bought a 1 inch spacer plate that was suppose to shield the carb. from the heat of the intake. It  has not helped. What spacer do I need and how can I make this engine idle when hot?

[67428GT500]

You really can't insulate the pump or the fuel line well. I have a 427 style filter and fuel line on my Shelby, but the fuel log even with Kevlar insulators between the intake and the manifold bolts doesn't keep it completely insulated here in NE Texas when it's over 100. I would imagine you're still getting some peculation. a 1" insulator wasn't necessary.  However. running the two 3/8 insulators under the Holleys made a huge difference.
I also know the Holleys were sensitive to fuel pressure as well. Do you have a stock pump? Do you know what pressure it puts out? I had to change the Carter pump because I was running between 7-9 lbs which made the issue worse before I installed the Edelbrock pump.
                                                                                                                     -Keith

[e philpott]

Does the choke go to wide open when hot ?

[GerryP]

...I bought a 1 inch spacer plate that was suppose to shield the carb. from the heat of the intake. It  has not helped. What spacer do I need and how can I make this engine idle when hot?

Depends upon what the spacer plate is made of.  If it's solid aluminum, then you haven't done much good.  An open aluminum spacer is much better.  Better still are the phenolic, plastic, and wood spacers.  There are also very thick gaskets that are good insulators.  You don't need a lot of thickness to insulate.  A quarter inch works.  Half inch and above you are using it as both an insulator and as a spacer to assist in performance.

[Ranch]

I’ve had my car for 48 years and it virtually the same as it was in the 70s cept now lower compression.  Back then never had a problem in traffic on hot summer days, why, the gas, no ethanol back then Gas was blended for cars with carbs to take the heat.  The fuel today is a killer for our type of engines and fuel systems.  So you say. How do modern cars get away with it?  Fuel injection and computers, sniffen, tasten and feelen, making all kinds of adjustments here and there.  I’m having the same problem with mine and listening to guys responses to my thread “EFI on a FE” I was enlightened on the one thing EFI has and I think most of us could find helpful and that is, an Electric pump at the tank, bring the fuel line up the fire wall to a pressure regulator with a return line back to tank.   When I had my mechanical pump I shot it with a tamp gun and it read 134* so I put a standard press. electric pump back at the tank, I could see a difference but still had problems.  So now my intensions is to go to high pressure pump, reroute my fuel lines up the passenger side and along the fire wall to regulator with return, and feed the carb.  Haven’t got into that as of yet but I would have to do this part if I was installing EFI so I figure I’m not losing any thing.
Gerry is right use a Phenolic spacer not aluminum   

[390owner]

Yes I have the one inch phenolic spacer. I have the gas line insulated from the pump to the carb. I also have an open k and n 4 inch air cleaner. Would an cold air system work better than sucking all the hot air from under the hood

[Drew Pojedinec]

Timing, carb tune, etc will impact this considerably.

You may not notice if your cooling system is good, but idling at 6 degrees vs 16 can make a huge difference in overall engine temp.