Carb spacer bore issues?
 

I have a phenolic carb spacer I got from a buddy. It's the four hole spread bore so I figured it would work with my Rochester Quad but the secondary bore is way too small. The spacer measures out to 1.9 while the carb secondaries are 2.2. Obviously they won't open. What's the deal here. I figured a spread bore is a spread bore. I'd hate to buy a different one just to have the same issue.

Up until now I thought they were all the same as you did. New to me. Hope someone can bring some light to this for future reference.

they are porobably meant to fit a spread bore HOLLEY.

Jroach got it. You need a QJet-specific spacer. They make 'em. I have one.

Well I guess spread bore isn't as all inclusive as I had thought :whine:

Who made it, part number? If I do a search with Quadrajet on summit I don't get any hits for a spacer. :( I had hoped Quadrajetparts.com would have one but I can't find it if they do.

How thick?

http://www.ebay.com/sch/i.html?_from...w=Q-Jet+spacer

here ya go dave one of the best companies that make really good hp building carb spacers ..


quadrajet/spreadbore tapered spacer ...


http://www.wilsonmanifolds.com/produ...ed-spacer.html

I never thought to look at eBay :screwup: Thanks

If you dont mind me asking, How important is a Carb spacer ?

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If you have the means, you can just port the spacer you already have.


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Carb spacer will alow you to find that last bit of OOOOMPH that you told your buddys wife you have. It will also keep you from closing many hoods!!
LOL

It depends on what you have. Factory intakes that were designed ti fit under a flat hood,left a lot of power on the table,as do some of the lower performance aftermarket intakes. An open spacer adds plenum volume to these intakes as well as improves the direction of airflow out of the carb bores and into the runners. An open spacer is almost always worth power in such a case.

A 4 hole spacers make the throttle bores longer which helps isolate the boosters which can often make the booster less sensitive to intake signal pulses while not adding any plenum volume.

A tapered bore spacer does just the opposite. It allows more of the induction signal to be applied to the booster with only a slight increase in plenum volume.such a setup is useful when trying to get fuel to flow out of the boostersduring low air flow. This is a good way to run a much larger carb(s) and still get signal to the boosters to keep them moving fuel.

A lot of time you need to figure out what kind of spacer your engine will like using dyno time and trial and error. In some cases like an engine with a stock intake or low rise aftermarket intake,you can almost always jump right to a 1" open spacer and see a gain(such is the case with my 400 smallblock with the low riser Torker 2 intake). In the case of an engine that has a tromendous amount more carb then it has airflow,a tapered spacer is almost always worth a gain. An example of that would be the 427 in my race car which probably uses about 750 cfm of air,but has an 1150 carb on it. It makes more power with the big carb butthe fuel cur e is much easier to get right with the tapered spacer.

Thanks Rich. That answers my question and then some.

here's the simplest terms for spacer


4 hole ....... allows more torque to be seen by the motor down lower in the rpm range and would be used if you motor felt lazy off the line


open hole spacer ..... increases plenum volume and the larger "taller" the spacer the more plenum volume it will create . also a open hole spacer will allow the motor to build more hp at the higher end of the engines rpm scale

Glad Rich steped in because I couldn't have answered it with any real confidence. I'm tinkering with them myself. I have the hood clearence and thought I'd mess around a little.