schrecke

I'm looking into replacing my intake and carb on my 74 L-82. Im mostly interested in the low end, off the line power increases. I've been concentrating on the Edelbrocks so far. What is my best intake choice (pros/cons) of the Performer, Performer RPM, and EPS. Obviously the carb choice will follow suit. Will all of these fit under my stock L-82 hood? I'm sure many of you have done this exact thing, so what type of power gains can I expect to see. Car is mostly stock except for Hooker side exhaust, Petronix electronic ignition.

Jvette73

Does yur 74 still have the original cowl induction breather? If so I would recomend retaining the stock breather and cowl induction setup. the Edlbrock #2101 intake is the same height as stock. if you go with one of the q-jet style carbs, it should all bolt up and line up for proper cowl breather height with no other mods. Im retaining the cowl setup on mine and am using the 2101,but I switched to a holley carb so I had to do some breather mods to keep it the right height for a good seal against the hood. in any event, stay away from the bigger carbs if yur looking for more bottom end. Im using a holley 600 and it does my setup fine. Its plenty of carb for my 350 up to 5500rpm and a bit further.

The Money Pit

If the rest of the motor is stock, save the money you'd spend on the intake and take out your wife for dinner. You'll be much happier.The stock cam won't take advantage of any increased flow potential the manifold swap would offer.

Ryan77

Use the Edelbrock performer EPS with the matching carb (check the Summit catalog, I think I saw it in there). I believe the carb is the Performer EPS 800. The EPS is the same as the performer, but gives 5 hp and 9ft/lbs more. It should fit under the stock hood with no problem, but I'd also buy an open element air cleaner too. I fit a the RPM under a stock hood by using a drop-base air cleaner. Like was said above, a mild cam change would do wonders for the motor with the intake/carb change. Good Luck :cheers:


[Modified by Ryan77, 5:57 PM 12/30/2002]

schrecke

Yes, the rest of the motor is stock. It does have the original L-82 cowl induction hood and air cleaner assy. The new Summit just came today!

schrecke

The carb is in need of replacement anyways. It's already been cleaned, regasketed and reassembled once. I figured while I was getting a new carb, not another Rochester Quadra-junk, I would go for the intake. I can take her out for one hell of dinner for the price of the Edelbrock intakes though...

Ganey

See CARBS Tests TQ/HP http://www.corvettefaq.com/c3/carbcomparo.htm

+ about 15. Probably you want 2101 or EPS. Weiand Action+ is good as well for what you want.

V8yunkie

I cannot see what's wrong with your Q-jet. It's rated at 750 cfm and with proper adjustment will outrun a Holley by means of power, throttle-response in particular and economy - just because its superior technology. Sure, it is a little more complicated to wrench on... but there's no advantage without any price. If yours is worn after over 20 years... is that a proof for a bad carb in general?

Get a new Q-jet from big E and safe yourself a lot of hazzle trying to adapt a holley to your cars surroundings. And a lot of fuel and black exhaust tips.

As the others said, there is almost no improvement possible just by changing intake and carb. And if you are after low end performance i.e. torque... believe it or not, but the stock cam is one of the best here.

Upgrades with sharper cams, bigger intakes, headers etc. always result in more horspower on the higher revs but reduced low end torque - and after all, torque will hit your back, nothing else. Torque off the pants is what excites me.

schrecke

Looks like a general consensus around here is that I won't see much difference changing the intake/carb unless I change the cams. I was planning on leaving the cams alone mainly because I don't know that much about choosing one. I don't know the benefits of one duration/lift combo to another. I see that Edelbrock is pairing some cams with their intakes now, but not too many people around here seem to use their cams, so can I assume those aren't so good. Is there a decent cam post around here like Ganey's carb or exhaust comparo posts? Thanks :confused:

Ryan77

You would probably want a Comp Cams 260H or 268H, the 260 will have the most torque.

Jvette73

schrecke, so yur car still has the cowl induction breather intact? If so thats good. I would keep it on there. You can still improve on it though by doing a few simple things.

1. Check in the intake area of the cowl tunnel and look for the flap. Its supposed to work by vacuum and open up under full throttle. Sometimes they get stuck in the closed position or become non- functional for some other reason. Find the flap and remove it to prevent any intake obstruction that may result from its presence.
2. Get a better flowing K&N filter for yur stock breather and also top it off with the K&N extreem lid which makes more filter surface from the top. This will insure that yur stock breather will be able to flow as much air as yur engine wants. I have both the K&N filter element and extreem lid on my cowl setup. the extreem lid is 11" diameter which is slightly smaller than the stock 12" lid. It sits just atop the filter with a 1/2" exposed on each side but fits, functions and looks fine.
3. Block the snorkles on the factory breather with a small piece of sheet metal and pop rivots. This will force all incoming air to be drawn from the cowl which will be cooler and denser than underhood air.
4. Make sure you got a good seal between the hood and breather and replace the seal if nessisary.

The cowl induction was made for a reason. Dont abandon it for a flashy aftermarket crome breather that will only have you pulling hot thin underhood air into yur intake.

Also you said you have pertronix ignition. Do you have any idea what your timing curve is on yur distributor? Tayloring yur timing curve can make a big difference in performance. Shoot for 14 degrees initial and 36 degrees total all in by 2500rpm. Taylor it to achieve this advance thru mechanical advance with vacuum advance disconnected. When done then re-connect the vacuum advance and connect to a ported vacuum source.

The L82 cam is a moderate performance cam already. Cover all yur other bases and it should run quite well. When tuned correctly the Q-jet is a great carb.

Are you runnin automantc or manual tranny?

schrecke

all the original hood cowl and breather equipment is in place still. I have not blocked the snorkels on the air cleaner assy though. The gasket on the air cleaner assy to seal with the hood looks rather squashed, maybe it could use a new one. I haven't yet checked for this 'flap' in the cowl tunnel, I'll check it out though. I'm just looking to give the car a little more go, not interested in running on the track for 1/4 mi or top speed or anything. A K&N was already planned for spring. I had originally been told that the Q-J was no good in general, and now I'm getting opposing opinions. I'm assuming people are only telling me this is the choicefor my stock engine. The Q-J is obviously not the choice for most people on the forum with their modded small blocks. Either way, I need a new carb. I've only had the car since April and its my first one so I'm collecting some information to help give it some life again before I go out and waste any money. And oh yeah, to answer your question, it has the original 4spd tranny. Why? Thanks for the input.

Jvette73

Just wonderin what yur tranny was since you didnt indicate before. 4spd!!! thats gotta be fun :cheers:

TedH

Have Lars rebuild your carb. Lars can make your q-jet work better than new. I suspect you have a lean condition now with the side-pipe headers and could probably bear some richening across the entire range. See if Lars is interested in the rebuild. If so, he will need the list of all of your mods along with your carb and about $180. You will be glad having dealt with Lars. He is top notch.

schrecke

For a stock L-82, is it your opinion that a Lars rebuilt, or new Q-J is preferred to an aftermarket Edl, Holley, whatever? Keeping the car original, the way it is right now (except for the wheels, exhaust and ignition) isn't that high of a priority for me. Having said that, does your answer change?

Ryan77

I haven't personally dealt with Lars, but everyone one the forum who has absolutely loves his work, and from his posts I can tell that he knows what he's talking about :yesnod:

schrecke

Yeah, the 4spd was a requirement for me when I was looking. Once I actually started shopping, I couldn't believe how may C3's were autos. I took a while to find a decent L-82 manual. The convertible wasn't on my list of things to have, but thats what I found and thats what I got. I understand its a personal preference or convenience if you will, and not to offend, by my idea of a sports car always has a stick. :steering:

V8yunkie

Schrecke,

reason for most people buying Holley or Edelbrock Performer (CARTER actually) carbs is that these carbs are cheaper, a little easier to work on and spare parts availability is a little better.

If you have a tuner with a great experience like Lars, the Q-jet will out-run the Holley with no problem. Holley carbs came from racing, where economy is not important rather than ease for quick jet changes and other mods on the track. Therefore they need to be simple. But a simple carb will never meter fuel as precisely throughout all the range of street driving.

If you run a holley on all-day drivin, you are up to create a lot of black deposits in your cylinder heads. This will show by increased power once you will drive the car on the Autobahn with high rpm for about an hours steady. I have had a 600cfm Holley and I live in Germany. But where in the US can you go at high revs for a long time?

The gain in throttle response, fuel economy with same or even better power after installation of my new Q-jet (Edelbrock #1902) was amazing. It took me some jetting and adjusting (which was fun, too) and now I am maybe 2 minutes slower in changing jets as on my old Holley. But with somebody like Lars near to you, this could have been done much quicker.

Regards,
Thomas

redwingvette

I have the performer 2101 intake and Holley 4175 650cfm carb. Have Lars redo your carb and make sure your distributor has the best curvse setup. Check Lars paper for that as well.

chewy

If you want low end keep what you have. You won't find anything better. When you have the carb off take a real good look at the sec. side of the manifold . If you have EGR they have a real bad habit of cracking through to the EGR passage giving you a full shot of exhaust gas into the intake charge at all times. I have found that smog motors like a lot of advance very quick. That will make the low speed feel much better.