Stock Holley 4000 Jet Size - 1956

[Shawnski]

I'm trying to figure out what was the stock jet size in was the 1956 312 Holley 4000 were? Automatic Trans

 

[paul5456]

You might want to contact Hill's or CASCO's tech line for that info

 

[Ward 57]

If you have the shop manual they specified different jets for cars that were sold at sea level and different jets for cars sold in Colorado. So many options at that time.

 

[knuckle47]

I pulled my 1956 carb, used with an automatic, and completely disassembled it so it’s In my basement spread across 8 feet of table. I have a spec sheet that reads: 0-5000 feet no.50, 5000-10000 feet no.49

I have a copy of Mike’s Carburetor Holley 4000 guide and even better, a good friend gave me a complete instruction sheet….thank you Doug!

 

[Shawnski]

Thanks Ward 57. Mine are .50 and when I pulled my spark plugs they were coco brown. I wanted this info just so I’d know for future changes if necessary.

 

[Ward 57]

Thanks Ward 57. Mine are .50 and when I pulled my spark plugs they were coco brown. I wanted this info just so I’d know for future changes if necessary.

I may be wrong but I think that's the right color. Not too hot and not too cold of spark plugs and a proper fuel mix.

 

[doug7740]

Ward is correct, light tan or gray deposits on the firing tip is a normal condition.

The chart below will help you determine the condition of your engine by looking at the spark plugs.

doug7740
1955 Thunderbird Blue