Steve.  It would be nice if it was as simple as you propose but it’s not.  The carburetor spacer is related to the specific engine combination and if simply changing a engine parameter such as the camshaft or the exhaust, then the spacer requirement also changes.  The carb spacer ends up being a part of the total tuneup where the intake tract length from the carb to the valve is working in tandem with the exhaust lengths and the camshaft overlap has a lot to do with the balance of those two lengths.  That’s an over-simplification but will have to suffice short of writing a chapter on the subject.

 

The tapered spacers do tend to work best in those instances where the engine is under carbureted.  The tapered spacer straightens out the air flow by reducing flow eddys under the carb itself thus permitting more air flow through the carb.  As a general rule, the better the heads are, then the more a tapered carb spacer tends to benefit engine performance in a particular rpm band.  There was thirty plus horsepower gain on my roadster engine in just playing with spacer designs.

 

I have Gary’s 312 stroker on the dyno right now and it’s in the process of testing nine different single four barrel intake manifolds on it.  All are ported differently.  With what’s been tested so far, it’s becoming clear that there is no particular spacer that’s going to be a fit all.  Certain intakes simply like certain spacer designs or spacer heights.  Once all the intakes have been run, then it’s a matter of sorting out the data and making some sense of it.

Lorena, Texas (South of Waco)

Ted, just finished reading that YBM article on the spacers, very interesting and again thank you for the testing results. Is this 4hole/open base style available or did you make it? best regards bill.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

This note has to be for Ted -

It almost seems to me, after reading doen through the thread - that there is a particular length of straight tube that needs to exist under the butterfly shaft. The combination of that uniform passage - and then the "diffuser" opening below does the deed? Looks like the section of straight tube must be something equal to (or slightly over) the full diameter of the butterfly below the pivot centerline?

 
 Steve Metzger       Tucson, Arizona

That is an interesting manifold, which somewhat parallels my thinking that the spacer should match the intake manifold at their pairing. Four hole, two hole or single open, it just didn't seem right not to have them matched, but then I haven't run one spacer test.  Some interesting info coming, my sincere gratitude for your endless efforts, in my case, without a complete build, every efficientcy is important.

Ted, Redding, CA

Here’s a link to a previous discussion regarding the tapered carb spacers.

http://www.y-blocksforever.com/forums/Topic67347-3-1.aspx 

 

And here’s another picture of the bottom side of a tapered carburetor spacer showing more detail of how this particular spacer transitions the air flow from the carb to the intake.

  

 

Here’s a picture of just a few of the carb spacers that have been tested.

 

Lorena, Texas (South of Waco)

Then a Moroso 64946 1 inch, 4 hole, 1.467" bore diameter it will be.  Drop shipped from manufacturer one week, $50 from Summit, with Moroso 2.5" carb studs $8. 

Having heck of time finding new 4 hole base plate gaskets to fit the Holley and ECZ-B, Holley shows them for around $20, I need 2, that ain't right and I'd cut them myself from paper stock. Anyone know a source?  Found it at NAPA, $1.53, had to go to RockAuto to get part #, then back to NAPA, NAPA site sucks.

Want to plug the exhaust crossover, seems I read thin aluminum under gasket on head side is that correct?

Thanks for the help. Gotta do search to sign up for Y-block Magazine. Found this one also, check in mail.

Ted, Redding, CA

The latest issue of the YBM does have an article on carb spacers and shows exactly how much power particular spacers are worth on the aluminum intakes.  Some of that information is transferable to the ECZ-B iron manifolds.  That issue is just now making it into the subscribers hands.

 

As a general rule for the ECZ-B intakes, the 1” height is preferred over the ½”.  For lowend torque, use a four hole and for upper rpm performance go with either a dual oval or open type spacer.  How the intake is modified will determine just how well a particular spacer will perform.  I'll add that the 'tapered' style of spacers (four hole on top and open on the bottom) still tend to show performance improvements on everything they are tried on.  If the intake is a four hole, then maintaining the spacer as a four hole typically gives the best results but even the tapered spacers tend to work on the four hole intakes even with the hole mismatch that's present.  If the intake holes have been elongated, then there are some advantages with other spacer designs that will come to the forefront.

Lorena, Texas (South of Waco)

C'mon bit more of a heads up on that one...  link?



"Came too close to dying to stop living now!"

Ted: The latest issue #108, Jan-Feb 2012 of Y-Block Magazine, has a very interesting article on carb spacers, by non other than our moderator Ted.. And guys, I wouldn't be so sure that the height & or shape of a spacer doesn't have any effect on performance.

Paul

I have a 1/2" 4 hole And I really didn't need to modify anything.. Not sure how you would go on a 1"...



"Came too close to dying to stop living now!"