Street Demon 625 Carburetor


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By 55blacktie - 3 Years Ago
Has anyone used the Street Demon 625 carburetor? Polymer or aluminum? Has the quality improved since bought by Holley? 
By Ted - 3 Years Ago
I have used several and all with polymer carb bowls.  Very responsive and good fuel mileage.  The three-barrel design using what they call the ‘goggle’ valve for the secondaries allows the primary side to be small thus promoting a very strong carburetor signal at low rpm. I have several years on some of these now and no issues to date.

Changing jets can be a bit cumbersome as the carburetor is a clean design on its top with no exposed screws so all the assembly screws come in from the bottom of the carb.  This requires the carb to be removed from the engine to change the jetting.  Another nuance is that the primary jets and metering rods are Street Demon specific so you’ll have to purchase a jet kit that has the appropriate jets and metering rods if desiring to change the primary jetting.

Holley does not own Speed Demon.  The Speed Demon and Street Demon carbs are owned by the same consortium that owns Holley and QFT carbs.  Been that way for several years now.  The Street Demon line of carbs were designed and marketed after joining ranks with Holley and QFT.  The quality issues you are thinking of likely goes back to when Barry Grant owned Speed Demon.
By Ted - 3 Years Ago
Here are a couple of pics.
http://forums.y-blocksforever.com/uploads/images/5db1d5d2-43ac-4fcb-a3fc-b75a.jpg  

http://forums.y-blocksforever.com/uploads/images/3af3a422-d1d3-4aff-8740-8b59.jpg  
By 55blacktie - 3 Years Ago
Thank you, Ted.