• Hello there guest and Welcome to The #1 Classic Mustang forum!
    To gain full access you must Register. Registration is free and it takes only a few moments to complete.
    Already a member? Login here then!

Topic change - Holley Tuning

Summit makes a spacer that is solid. I'm using one on my boat to add PCV to it (not required on boats until 2000 or so). For the boat, I had to open it up with a grinder (weber WFB carb isn't exactly the same as Holley et al), but it fit my square bore carb on the car no issues.

http://www.summitracing.com/parts/SUM-G1400/
 
I think I might have one of those in the attic!

What about the PVC issue?

I'm running searches here and on ahem, another forum I used to use frequently, to find the answer, as I'm sure this gets covered about every other week.

So far best option I've come up with is to simply turn the spacer upside down. Solid metal on "top" would seal gap against intake, and open "bottom" would seat against solid Holley base plate.
 
After yanking the carb and looking at the fit, I'm not sure the spacer upside down will work with the various vacuum indents on the bottom of the carb baseplate.

I'm going to try to find one of those thin 3/8" spacers with the PCV fitting like the Boss 302 used, or just shove the PCV into the rear of the intake.

If I tune the carb without the 3/8" spacer, will the tuning need to be changed if I add the spacer back in?

The port I'm talking about using for the PCV is one of these as pictured, the other being used for the power brakes:
s7ms2.jpg
 
I doubt the spacer will effect the tune enough to worry about in terms of changing jets or anything like that.

I used to have some flat aluminum heat shield type plates layered in my built 302 to keep from boiling the gas, they would be perfect because they extend beyond the spacer. I'll see if I still have them somewhere...
 
no, I had a 12.5:1 compression and a big valve overlap cam. For some reason when I shut it off, it would boil the gas out of the carb from heat in the intake manifold. I had a lot of advance in the timing too so it was a bear to restart. Anyway, when I sold the short block (many years ago), I kept the carb and those plates. The carb is long gone, but I think I still have the plates in a box.
 
You are better off running the PCV to the carb spacer, as then the crankcase gasses get distributed to all cylinders instead of just the ones in one plane (and generally, just the back ones in that plane). There are lots of cars running them to the manifold, though. Only ones I've seen with a probelm from it had lots of blowby - which should not be a problem for you.
 
You can run the pvc tube to intake runner without a problem.
As far as the fuel boiling, It may not effect your carb.
The best reason to use the spacer in this case is power output will be increased with it.
Also you will notice a much better drivablity with the spacer in place.
The carbs retune will only be resetting the idle mixture screws for smoothest idle performance.

On a side note, IIRC the screw plug just below the sec vac pot is a pvc port in the carbs base plate.
I used this port on a 600 a few years back.
 
I'll check to see if I have a port in the base plate. Otherwise I plan to just get the Boss 302 style 3/8" spacer with PCV port and use that.
 
You must log in or register to reply here.
Back
Top