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I put my pcv on the manifold simply because I didn't want to risk having nasty crankcase fumes blow into the carb. Probably not a fear, just a consideration.
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Please don't post advice that tells people to connect the PCV system to the manifold port.
Please don't post advice that tells people to connect the PCV system to the manifold port.
That is correct. If anything put the power brakes to the manifold. PCV has to be at the carb base to equalize the A/F ratio or you will be running the cylinder the manifold port is connected to much leaner than everything else. Good way to smoke a piston. The nasty crankcase fumes are drawn in under the carb and evenly distributed and diluted to all 8 cylinders, not run through it. You should know better being the top tier knowledgeable mechanic you are.
That is correct. If anything put the power brakes to the manifold. PCV has to be at the carb base to equalize the A/F ratio or you will be running the cylinder the manifold port is connected to much leaner than everything else. Good way to smoke a piston. The nasty crankcase fumes are drawn in under the carb and evenly distributed and diluted to all 8 cylinders, not run through it. You should know better being the top tier knowledgeable mechanic you are.
Yes, I know, that runner is bit a leaner.
Like I said, I wanted to see if it would cause problems. But it hasn't yet. I may just switch them.
I got tired of oily fumes and mess all over the base.
Re-read the Super Chevy story above. Their dyno is not set up to be biased. I'm not saying Lars is trying to rip people off or anything, but he does have a business restoring Q junk for goodness sakes!!!!
OK. Read the story.
40 year old Quadrajet pulled 205 HP, 284 ft lbs with only mixture screw adjustment. No other changes, rebuild or modification.
Holley 750 HP (no choke plate) pulled 207 HP and 298 Ft lbs with Jet changes
Brand new Holley 670 pulled 199 HP and 287 ft lbs with jet changes
Difference is zero seat of the pants and negligible to nothing on the track. With a little minor tuning the 40 year old quadrajet would pull same or likely better numbers. You do realize the way the story is written, Quadrajet (enter your favorite detracting name here) and the fact Holley is a huge advertiser this "story" was written to sell product right? Also the carb change would have required an intake change also. They failed to mention that.
OK. Read the story.
40 year old Quadrajet pulled 205 HP, 284 ft lbs with only mixture screw adjustment.
Holley 750 pulled 207 HP and 298 Ft lbs with Jet changes
Holley 670 pulled 199 HP and 287 ft lbs with jet changes
Difference is zero seat of the pants and negligible to nothing on the track. With a little minor tuning the 40 year old quadrajet would pull same or likely better numbers. You do realize the way the story is written, Quadrajet (enter your favorite detracting name here) and the fact Holley is a huge advertiser this "story" was written to sell product right?
How come every comparison of Q junk to Holley starts similar to this?
This, from the article with the q junk on it.
"We started out by baselining the Chevelle, but had to abort the first pull because the air/fuel reading showed that the engine was way too lean (16.1). After adjusting the mixture screws on the the Quadrajet, the 396 pumped out 199 (corrected) horsepower and 274 lb-ft of torque."
And General Motors isn't an advertiser? I'd wager they spend considerably more than poor lil ole Holley
How come every comparison of Q junk to Holley starts similar to this?
This, from the article with the q junk on it.
"We started out by baselining the Chevelle, but had to abort the first pull because the air/fuel reading showed that the engine was way too lean (16.1). After adjusting the mixture screws on the the Quadrajet, the 396 pumped out 199 (corrected) horsepower and 274 lb-ft of torque."
And General Motors isn't an advertiser? I'd wager they spend considerably more than poor lil ole Holley
The more interesting thing about that quote to me is that they somehow corrected a dyno pull via the mixture screws... idle mixture will have virtually zero effect on a WOT dyno pull.
God knows how they tuned that thing. Although it's probably safe to assume it was just lazy writing.
But the Holley ULTRA Street Avenger has a PCV fitting on the front of the carb, so why not use that. My previous statement was that the Quick Fuel SS does NOT have a front fitting.
I really am leaning to the Holley, just because of its long history of success, but I have never read ONCE that an anyone had issues with a Quick Fuel carb, and most of the time people comment that the Quick Fuel is better quality and more features, than Holley. So, I have no idea why they chose to NOT have a PCV fitting on the front like Holley does.
Just to be clear and in the spirit of honesty and not plaigerizing.
I put the PCV on the runner simply as a test and have not had any problems. I check the plug, and it doesn't appear to run lean.
But to be honest, I've switched it back. Easy to do, and the hookup is still the same as in the photo, just the manifold runner to the Booster, and PCV to carb.
I have seen it done both ways, and there are proponents for both. Some say the oil in the fumes mixture makes up for the extra air.
I don't know, but I can't see any real advantage.
Factory hookups for the booster are on the manifold runner.
After 108 postings, I have made my decision. I am sending my original to Lars for rebuild and removing the brand new Performer RPM squarebore (see pic, now for sale) and buying a Performer RPM Quadrajet. I believe the rebuilt QUadrajet will be all I need AND I don't have all the following problems:
- Holley style carbs will not fit on the manifold and provide room for the vacuum fitting on the Performer without spacers....and we all know hood clearance is at a minimum without adding spacers.
- Quick Fuel SS carb only has one large vacuum fitting....why I don't know, but this is a problem when I need Power Brake Vacuum, PCV vacuum, and headlight vacuum.
- Ultra Street Avengers DO have two large vacuum ports, but I still would not be able to use the intake vacuum fitting.
- Do not like any of those Lokar style throttle brackets, so no good options that seem sturdy enough
- Edelbrock AVS was really going to work well and an easy install, but I just felt it was a compromise. I could not be satisfied with the issues I was reading about.
- All of the above required different fuel lines, throttle fittings, etc. The Quadrajet will be easy with stock parts....except maybe the fuel line. Not sure if the additional height of the RPM will work with stock fuel line.
In the end, the Quadrajet was the least amount of trouble, and way less money. I always believed it was a good carb for me and do not see it a compromise in any way. I am not race boy and I from what I read, I think its quite a capable carb if I was. There are many many people who have good things to say about this carb for a strong street motor, which is all I care about. No intentions of racing.
Thanks for all the input....!
Last edited by Torqued Off; 02-18-2015 at 10:20 PM.
After 108 postings, I have made my decision. I am sending my original to Lars for rebuild and removing the brand new Performer RPM squarebore (see pic, now for sale) and buying a Performer RPM Quadrajet. I believe the rebuilt QUadrajet will be all I need AND I don't have all the following problems:
- Holley style carbs will not fit on the manifold and provide room for the vacuum fitting on the Performer without spacers....and we all know hood clearance is at a minimum without adding spacers.
- Quick Fuel SS carb only has one large vacuum fitting....why I don't know, but this is a problem when I need Power Brake Vacuum, PCV vacuum, and headlight vacuum.
- Ultra Street Avengers DO have two large vacuum ports, but I still would not be able to use the intake vacuum fitting.
- Do not like any of those Lokar style throttle brackets, so no good options that seem sturdy enough
- Edelbrock AVS was really going to work well and an easy install, but I just felt it was a compromise. I could not be satisfied with the issues I was reading about.
- All of the above required different fuel lines, throttle fittings, etc. The Quadrajet will be easy with stock parts....except maybe the fuel line. Not sure if the additional height of the RPM will work with stock fuel line.
In the end, the Quadrajet was the least amount of trouble, and way less money. I always believed it was a good carb for me and do not see it a compromise in any way. I am not race boy and I from what I read, I think its quite a capable carb if I was. There are many many people who have good things to say about this carb for a strong street motor, which is all I care about. No intentions of racing.
02-07-2015, 04:40 PM
