I have been looking at carb spacer. I measure the intake holes ( 1.5” ), and carb base Ventura ( 1.5” ) . But looking at spacer they are 1 11/16”. Am I not finding the right spacer or do I not know what I am looking at. The carb. Is a Holley 570 street avenger. Any help with this would be great, as I what to do it right the first time.

Best bet for Electric Choke Power is right from Ignition Switch. Also ad an inline Fuse to protect the circuit in case of problem.

  

A one inch four hole is the best bang for the buck for most street Y engines.

Lorena, Texas (South of Waco)

I put a 1" spacer under my carb to help alleviate a heat soak issue.

Durham Missouri

Ted What size of carb spacer would be best to use?

If the car already has a choke cable, then you can go with either electric or manual choke.  If no choke cable, then it’s usually easier to go the electric choke route.  The Holley electric chokes work well but if running a 12 volt power wire to the carb, be sure it comes from a source other than the coil.  You don’t need the voltage drop that results from hooking up accessories to the positive side of the coil.
 
Here’s a picture of a carb and spacer being installed in a ’56 Ford with a standard shift tranny.
 

Lorena, Texas (South of Waco)

Thanks all for your responses. Have read about possible jet charges. Would you have any photo of the spacer and linkage.should the chock be a Manuel , or electric. The setup now is 2V with Manuel , had no issue with that.

i have the same carb on my 292 in 49merc pickup.i had to enlarge main jets to eliminate the bog. also the new hollers have a seal isue with b manifolds. i made a spacer that better seals the newer carbs to b manifold. 1/4 in alum plate ,made templet re the new carb to acomedate a home made gasket that has a complete seal. this plate sits on a plastic spacer(plate goes between carb and plastic spacer) be sere to get clearance on the choke sid as well as throttle side, little work but made a big difference. i use elect choke

Yes on the spacer but make sure it is a 4-hole or divided spacer to preserve dual plane functionality.  As tall as you can fit under the hood.  If you have the money, get several different thickness and style spacers to try.

For tuning, there are many books about that and many about Holley carbs in general.  Get one of those if you are new to it.  Otherwise, it's practically the same procedure you would use with any other carb.


Lawrenceville, GA

At the minimum (IMO) you should have at minimum a 1/4" phenolic spacer to minimize heat transfer to the carb.

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