Hi Y'All

Urgent Help Please...Need To Buy Shortly

Just wondering if anyone can help me....I've recently purchased my first Corvette...Its a 1975 Corvette Stingray Coupe Automatic T/top...It has a new Crate Motor whcih is a 350 chevy & we believe has a mild cam in it...its a 290Hp
I'm just about to change from the rochester carby to a Holley 600 & i've been told to change the intake manifold as well so i will be buying an Edelbrock Performer Intake Manifold Endurashine

Now to my questions....I have seen Standard Air Cleaners, Edelbrock Cleaners, K&N air cleaners...standard ones are cheap at around $40 where as for a K&N which are around $180...the K&N has the top as a filter as well......Is there much difference between the basic standard cheap one & the higher priced ones?....which one do you use or know is better & why?

Cheeeeeerz
Mike

 

I have a 69 350/350... I have run both the OEM style and K&N (also in modern cars) and Ive found that its more important to make sure its clean.

I prefer the OEM paper style because I prefer the throw-away no maintenance. With the oil-lubed filters, it can become a hassle when oiling (too much vs too little, too much results in oil particles everywhere etc).

Andrew

 

 

I got the elderbrok filter looks amazing

 

Filters do make a difference. The K N style flows much more than any paper filter.
Fit the largest one you can under the hood.

 

What's wrong with the carb and intake on the car?

 

I use a K&N 14" filter with their filter top. Here's a thread I did on a cold air inductions setup I built to lower the air temperature coming into the engine. Post #63 is a video that I made of the results, so you can see the difference between the cold air induction, and the engine bay temperatures that a regular under hood air cleaner would be taking into the engine. I'm guessing a 20-30 hp increase due to the lower intake temperatures. As I get on the throttle, the temps under the hood rise, while the temps in the cold air intake lower.

http://forums.corvetteforum.com/c3-t...80-hood-4.html

 

Use the largest, best flowing air cleaner you can fit under the hood. Forget the bug eyes.
I have a '74 which uses a low profile element. I swapped in K&N element for a '77 which is almost an inch taller (I needed to get a longer stud to hold it).
Big difference at highway speeds and above. The improvement in torque from 55 to 80 mph is delightful. Just a toe squeeze on the throttle, and you've passed that guy. Great fun.
I use a K&N on my daily driver (96 Crown Vic), as well. I noticed a nice improvement in midrange torque there, too.

 

A friend and I went to a dyno shop, myself with my 79 and he with his 80. I have a stock twin snorkel air cleaner with all the duct work and a k&n filter modified to work on a Holley carb. I wanted to see what the difference was with the 14 in open air cleaner was so for one pull I used my friends air cleaner and made 10 less HP with the open air cleaner than I did with the stock one. Also this is not a stock engine, 335 hp at the wheels.
I believe that its mostly because even with the hood open the stock air cleaner is pulling in cold air from in front of the radiator. Also I think the because I have a clutch fan that there might be a lot of turbulence around the open air cleaner causing it to not flow as well.
Just for fun we did a pull with no air cleaner and dropped another 15 hp from what I had with the open air cleaner. On this pull it was really rich over 4000 rpm. The dyno shop tuner told me its because of the air flow from the fan blowing over the carb.
Good luck

 

Sounds like "he was told to change them".

 

K&N are an excellent product and I use them almost exclusively - they're not, however, perfect. Most notably, ask any line mechanic at a dealership what they think of them and they'll all say this "they're terrible to MAF sensors" - the oil comes off, and coats the sensor... especially, if you put too much oil on the filter.

If you going to drive the car a lot, the K&N filter is excellent because it will get you better mpg, and better power... however, unless you're going to drive it to the million mile guarantee - I'm not sure it's worth the cost difference.

But they do look cool, and filter tops work pretty well as well...

 

Hi Everyone & iotto

Thankyou for your replies....iotto my rochester has a worn main shaft which my mechainc said is not worth a re-kit as better carbies are at good prices...My mechanic suggested i put a holley 600 on car & if i do its better to change with it the manifold to have a Edelbrock performer manifold..he said i would get much better throttle response/more torque etc
I tend to agree with "Gluvnaa" about the paper ones are throw away & replace as what is the correct way of oiling K&N Air Cleaners...what is too much or not enough oil,,,,but i guess it all comes down to if its worth the extra $100+ for the more expensive air cleaners???

Cheeeers
Mike

 

If any of you actually believe that a change of air filter will really give a true power increase, I've got some nice oceanfront property in Utah for you.

 

Can you explain how increasing air in through the filter and carb wouldn't increase power?

 

Rebushing the throttle shaft is really quite easy. I wouldn't trust your mechanic to work on it though.

That said, if it's the original 75 Quadrajet they are somewhat difficult to tune as they have a different part throttle metering setup than other years. I'd personally swap it for a 77+ M4M QuadraJet.

If the car is currently driving well, there's no reason to change. You'll have better torque and throttle response with the stock intake and carb, despite what your mechanic says. The primaries on the QJ are smaller and more efficient than those on a Holley 600.

 

Im a cheap *** but if it were me Id re bush it ( if it needs it ), maybe even throw a rebuild kit at it and be happy.

Do you know for a fact the shaft is leaking? They are loose and do have some play.

What are your symptoms?

On that engine, I doubt adding a performer intake would gain you much other than a little bling.
Its your car so at the end of the day your decision....just trying to save you a few $$$

And Mike, any pics of that residence, Im interested!

 

I use K&N filters in most of my vehicles, but I throw them out when they get too dirty. when you re oil them they are never the same

 

The design of the filter 'housing' (air cleaner hardware) is likely more important than the filter media. Having an 'open' design certainly provides ample access to air. But, fluid dynamics also plays an important part in this, I suspect. If the air cleaner inlets appear to be a "restriction" to you, it could be because that is intentional.

The 1963 Corvette air cleaner comes to mind on this issue. If you recall, it has two tapered snouts that provided no more opening to air than the size of 2 pingpong ***** (or golf *****). Compared to the size of the air filter inside the housing, they looked TINY. But, I've been told that those restrictions, followed by those tapered inlet tubes actually caused the air velocity at the filter to be increased! Thus, that air cleaner provided allowed better engine performance than an open element cleaner would do.

Chevy Engineering did a lot of testing and evaluation of all its product designs. I can't imagine them putting that crazy air cleaner on that engine if it didn't out-perform an open element design.

Bottom line: Don't swallow all the hype on high $$$ 'gadgets' for your car. If you want to spend big money on "stuff", you need to have some evidence that such items really do improve something before dumping cash on them.

P.S. Repairing a throttle shaft bore on a usable Q-Jet is MUCH less expensive than buying a new carb. You will not improve engine performance by switching to a Holley. And, if you want to see if the "loose throttle shaft" is significantly sucking air, just plumb a vacuum gauge into your intake manifold vacuum connection and take a reading when the engine is idling. Then pack a little clay or Play-Doh around the ends of the throttle shaft(s) at the [supposed] "gaps" between the housing and shafts. Read the gauge again. If there is little [or no] difference in readings, the shaft isn't really that worn. Not to mention that such a vacuum leak would only affect the carb during an idle condition. Once the carb starts to open, any piddly amount of leakage at the throttle shafts would be incidental.

 

Hi Mike,

I went with the Moroso 14" low profile drop base racing air cleaner.

Along with my Weiand x-celerator intake manifold and Quick Fuel 750SS carb, everything fits under the stock hood nicely.

Incidentally, if you are going to change out the intake manifold, I would consider a Weiand Team G or Edelbrock Victor Jr instead of the Performer intake. Both will provide more HP and TQ and have low carb mounting pads. I recently read an article in one of the performance magazines which did an in depth test of many small block chevy intake manifolds, in the tests they found the Weiand Team G and Edelbrock Victor Jr to be amongst the best and they were also amongst the lowest height intakes available.

I've also recently purchased a 14"X3" K&N air filter element to replace the paper element. I've used K&N filters on my daily drivers and found them to be an good addition to provide additional air flow.

There have been tests done on the air cleaner style and the K&N filter element that suggest that both have benefits compared to the standard air filter and element.

Besides, having the stock 77 air cleaner on my new engine just didn't look correct. JMHO.

 

Hi Guys

Thankyou for your replies

Understanding.... i'm no where near the knowledge of a mechanic....my car was at the workshop & was running rough which the mechanic said was not the Msd ignition or leads....He leaned over & grabbed the side of the carby which he said was the main shaft & wiggled it a little & the engine was revving up & down off of idle...this is how he told me the shaft was worn, he mentioned it seems to have been re-kitted before & was best to replace with a holley600......Replies are welcome

Cheeeerz
Mike