General Category > Quadrajet Carb Talk and Tips
Float level and other Qs
Cliff Ruggles:
Is the spacer 4 hole, fully divided, or open?
Macadoo:
Hey Cliff,
It's a four hole phenolic. It wasn't real flat when I bought it but it sanded flat pretty easy. But I don't think I can take a 1/4" off by hand. Although I do have a wide belt sander at school.
Macadoo:
Oh, and the carb/spacer are sitting on an Edelbrock performer dual plane manifold.
Macadoo:
A small update: my dial-back timing light is a POS. I put my old light on it and, although I can't see the timing mark since it's so advanced, the nicks and other marks on the balancer are rock-solid steady. I'm making a timing tape and will get it on tomorrow. I was real close to pulling the distributor to have a look at the gear.
Cliff Ruggles:
I've done a lot of testing with spacers and have found them for the most part to be a waste of time/funds.
They create issues by raising the carb up higher, like hood clearance, choke tubes, throttle cables, etc.
On my 455 making over 550hp I did some drag strip runs back to back with 4 different spacers. 4 hole, fully open, fully divided and semi-open (divided in the front and open between the secondaries.
I also drove the car on the street with all 4 of them to get a "feel" for how well they worked there as well.
The 4 hole and full open were horrible at the track, slowed the car down everyplace and the fully open induced a huge stumble going to full throttle.
The fully divided did OK, and I ran the highest MPH with the semi-open.
However, when the smoke cleared and dust settled, the quickest ET was with no spacer at all, just a 1/4" thick factory gasket.
I also did some intake testing. The Edelbrock Performer was a "turd" on my engine, and couldn't even make a full throttle pass as the runners are smaller in cross section than a stock one. The engine hated it. The RPM did fine, and I also tested a Holley Street Dominator, Torker and Tomahawk.
All the single plane intakes ran slower everyplace than the dual plane, and required a 1" open spacer to work well. The Tomahawk ended up running the highest MPH but slowed the car down considerably in 60' times. Once again the factory iron intake ran the quickest ET, so it was making the most average power.
Folks in the Pontiac World cried "foul" because I had modified the iron intake by opening it up under the carb to the same apprx size/shape as the RPM intake.
For SBC builds it is hard to beat a stock iron intake to at least 450hp. They are excellent, low profile, very well made, etc. Even so we see them tossed out all the time for aftermarket intakes and folks think they are making more power.
A few years ago I did some back to back dyno testing with a 428 Pontiac engine. It had aluminum heads on it flowing 260cfm, 10.7 to 1 compression, and custom ground 236/242 hydraulic roller cam in it. I tested a factory aluminum HO intake, Edelbrock RPM, and my "modified" iron intake.
The HO made 487hp, the RPM 491 and the iron intake 497hp. Keep that in mind when you buy a Performer, Performer RPM or even the larger Air Gap version for you little SBC engine build make considerably LESS than 500hp.
Looks like you may have found your tuning issue. No real need for timing tape, I just measure over with a tape measure and put a mark at 36 degrees with a paint marker. You can reference off of that mark when setting the timing, etc..........Cliff
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