five7kid

iTrader: (14)

Okay, long-term planning (dreaming?) time...

In a little over a year, the Camaro will go through emissions testing for the last time. After that, it will be eligible for 5-year "collector plates" before it's due again, and as long as you don't let those expire, you don't have to go through emissions inspection or testing in Colorado.

I've read the Steve Green "Stroke in the Desert" HR mag articles on the Board, where he put a 383 in an '83 'Bird LG4 set-up, had Jet do his carb & PROM, and passed emissions with flying colors. Well, as stated, I won't be worrying about emissions, but obviously he got this working with a much larger engine than the factory intended, so this "dream" keeps recurring.

Step 1) The '57 gets a 502, or some Monster Mouse (ZZ383, Motown 434, etc.). Regardless what happens, the old girl will get the highest HP/weight (meaning HP has to be >> than the Camaro), enough to keep at least a fender ahead of the Camaro.

Step 2) The Camaro gets the 396. Now, the easy thing would be to just do the Holley thing, but this will still be the daily driver (I presume - spending so much on the '57 will most likely dictate that). That's why I'd still consider the CC system. Cowl hood is assumed either way. Now, I know the factory never did this, but the carb and distributor mount the same whether SBC or BBC. Other than that, we're just talking sensors. The knock sensor should screw into the BBC water jacket drain, just like the LG4. EGR no biggie, just hook up the solenoid and fool the ECM into thinking it's doing something. A.I.R. I already know doesn't feed back to the ECM. MAP, BAP, CTS - shouldn't be an issue. O2, just put a bung into the exhaust. The cam in there now is pretty mild, should be able to retain it without causing ECM brain farts.

Power steering - I have the original brackets & pump for the engine. AC - might have to think about that one. Delete would resolve other issues.

Of course I understand about tranny and rear upgrades.

So, other than reaching for the phone to call the guys in the white jackets on me, do you see any glaring problems preventing this from actually working?

Apeiron

Might want to see if you could find a knock sensor from an engine with the same bore as the 502.

Bunker82

On the knock sensor issue...if you can't find a suitable one, you can run an early LG4 CCC setup like mine had that doesn't use a knock sensor.

five7kid

iTrader: (14)

The 502 is for the '57. The 396 bore is 4.124". A 454 is 4.250" - close (what's an eighth of an inch between friends?).

However, the block is supposed to be the same casting as the 4.250"-bore 427 - hmmm...

I kind of like the idea of a functioning knock sensor. Don't think I want to convert to an earlier system (might as well go non-CC in that case).

chevymad

So you thinking 454 tbi knock sensor? Might be tuned close enough. Dont really see any other problems with the idea.

paul_huryk

Theoretically you can run a big-block if all the sensors are working and everything is tuned. Since you can use a q-jet on a big block, the distributors are the same, and the TCC hookup is only a trans-related item, it can be done. You don't need to do the air tubes or anything - although it will work if you want. EGR can be hooked up too.

Or you can run a 400ci+ small block - just keep in mind that a factory q-jet can support 500hp or so with the right tuning.

five7kid

iTrader: (14)

There's one main thing holding me back on a bigger SBC for the Camaro - I don't have one.

If I can swing one "bigger" engine, it will go into the '57.

But, one option would be to bore the 396 out to 4.250"; I've already gone through that build-up on paper (talked to Comp about a solid cam, Stealth manifold - that would basically cover it unless I also reamed the seats for 2.19/1.88" valves). That would hinge on the sonic check of the cylinder walls, of course. Then, a 350 shortblock for the Camaro (I could use my current heads on a 350), or 383 or 406 (probably have to go with different heads with that much displacement).

That may actually cost less than a bigger/different engine for the '57 and the 396 for the Camaro. I could do the larger SBC for the Camaro now, in fact, but I'd rather speed up the '57 first.

Keith_Indy

At most I would think you might have to change the program for the bigger engine. Tweak the timing curve and what-not.

Otherwise, I don't see why it wouldn't work.

Keith_Indy

Found this thread with some relevant info...

https://www.thirdgen.org/techbb2/sho...hreadid=134281

RB83L69

The biggest problem you'll have is getting an idle circuit designed to feed an appropriate amount of fuel for a 305 at a given veccum, to feed enough for a 454 at the same or possibly less vacuum.

The main sysem will be fine, and of course the secondaries are easy to dial in.

Idle is where it will cause trouble, if anywhere.

Air_Adam

Yup, I agree. Idle will be the most trouble to get right with a CC Qjet. If its a 'limitted' carb, you might wanna grind off the limitting tabs on the secondaries so that they can feed a 396 (427?) at WOT. I doubt the ~550cfm limit is anywhere near enough for a 400ci+ motor.

five7kid

iTrader: (14)

I remember that thread. I had done my mods before that, with a JC Whitney chip (which I don't think they even have anymore). The ECM was completely happy with the change from stock LG4 to the extensive mods (just adjusted idle speed and choke pull-off).

I don't think I'd bore it out if I put it in the Camaro. Not sure if the knock sensor would be that unhappy.

I've seen talk about modifying the idle circuit. I'd have to understand that thoroughly, or have Jet or someone similar work on it.

The secondaries have always been capable of full-open AV since I've had the car.

Damon

I've done swaps with cc-QJets onto larger motors, but never anything over 400ci. The carb and ECM are amazingly adaptive to large changes in airflow from bigger cubes and performance modifications. Not at all like FI.

I never had to modify the idle circuits on my motors- maybe I was just lucky. Just played with the IAB to get it to stay in closed loop at idle and not throw a code. Usually, of course, this meant making it richer (turning the IAB clockwise). If you find that you have the IAB all the way down and it's still too lean, then go to the idle mixture screws and put them out like 7-8 turns and try again with the IAB setting and see if it's now rich enough. Only AFTER you try this would I recommend getting the idle circuits modified. Idle circuit mods on a Qjet are basically irreversible, so you don't want to do them until you KNOW you really NEED them modified.

Change the original LG-4 secondary rods and hangers out for a set of "DA" secondary rods and a "G" hanger as a good starting point for a safe/reasonable WOT A/F ratio.

Other than that, I'd bolt as much of the stock stuff back on as possible, including the stock EGR and knock sensor systems. This is going to be plenty challenging a project, so change as little as possible just to get it running and tuned reasonably close. THEN play with mods to the chip, knock sensor, EGR, etc. later and see if it helps.

five7kid

iTrader: (14)

I had the DR/B's in a 1901 Edelbrock q-jet that I had on the 396 up until the fall of '01. They seem to work quite nicely in both carbs on their respective engine.

The BBC intake manifold I have doesn't have EGR, so that's why I thought I'd just plug the solenoid in so the ECM stays happy. The only thing I saw with the stock LG4 when the EGR ports were plugged shut with carbon was I couldn't run much more than factory base timing or I'd get part-throttle loaded pinging with regular grade unleaded.

Before my last emissions test, I turned in the mixture screws because I couldn't get it lean enough with the IAB - I set the IAB in the center then screwed in the mixture screws until it started having an effect - actually put them a little leaner than "optimal" to increase the chance of success on the dyno, which seemed to work. I've just left them that way, about 2 turns out.

I would stay with the present 401 CID (.030"-over 396) if it goes into the Camaro, assuming the cylinders look as good as they did last spring when I had it open for the head porting. I know, I know, a 400 SBC would be a lot lighter, but, I don't have one of those.

RB83L69

Be careful trying to fatten it up with the IAB. If you try to go too far with it, you'll end up restricting the ability of the solenoid to spring back up to the "rich" position, and the rods will never come up out of the jets like they're supposed to.

This is exactly why I don't like modifying junk Q-Jets. There are certain of the old carbs you can get that already have good adjustment ranges and large enough orifices and all that; but I don't have the vaguest idea where to go to find that in a CC one. Right now, for example, I have a 7029202 on my Land Yacht's 454; even though the carb is for a 350, it still has large enough idle orifices to feed the 454. I doubt you'll be able to find a CC carb with a satisfactory mix of both large CID setup and performance settings, because there never really was any such engine.

I eventually gave up on the CC carb when I had it on a 400 in my 83. But, I had a pretty big solid lifter cam in it then too, so I only had about 14" of idle vacuum @ 800 RPM, which is already WAY low compared to what the stock motor would have had; and since the idle system feeds in proportion to idle vacuum, the combination of low vacuum and big inches was a double whammy. I never could get the idle and off-idle driveability issues worked out. I finally put a Holley 6211 (800 CFM dbl pump man sec spreadbore) on it, and that was wonderful. It was the exact right thing. Fixed it right up.

But good luck, let us know how it turns out.

five7kid

iTrader: (14)

To revisit an old "friend"...

As you can see from the current sig (it says: "In the works: ZZ4 shortblock" - in reality, it's probably an early ZZ3 or older block), this is probably OBE (overcome by events).

Since the factory used the CC q-jet with only secondary rods/hanger and PROM change for the now-defunct HO 350 Camaro Conversion Kit based on the ZZ4 crate motor, my CC carb system should support this new displacement without too much complaining. I've got an eBay ZZ4 cam on the way, the block will be bored .030"-over to clean up the walls, I'll use the ported iron 58cc heads now on the 305, hyper pistons with an additional 5cc dish over the typical flat-top 4 reliefs and composition head gaskets to control compression. The intake, oil pump, & baffle in the 305 are already ZZ4 pieces. My JC Whitney chip will be given the nod until proven otherwise. My headers are better than the manifolds the Kit used. Tranny has already been upgraded. Poly bushed boxed LCA's will be done as time permits.

The CC BBC would have been "unique", though, wouldn't it?

Damon

If all you need to do is make the whole idle system richer for some reason it's easy to do- just drill out the Idle Chammel Restrictions like on an old non-CC Qjet. They're still in the casting in the same place as always. Just remember that such a modification is irreversible and so should be done in small steps.

Also, bigger cams play more havoc with a computer controlled setup more than cubic inches do. At idle big cams have a lot of "overlap" and so pump a fair bit of unburnt fuel and air directly into the exhaust. This does funky things to the O2 sensor's readings at very low RPMs (under 2000?) and the ECM tries to compensate based on false information. Typically, it will end up leaning out the idle and off-idle trying to keep the mixture at 14.7:1 based on what the O2 is telling it. It will fail. And if it doesn't throw a code it will run like crap at idle and off-idle when it goes into closed loop because it's making the mixture leaner than it should be for good running.

I suppose you could burn a chip that shoots for a richer A/F ratio at idle and off-idle (13.5:1??) but I have never gotten to that level of experimentation myself.

If you keep the cam under about 225* @ .050 on a 112* or wider LSA on a 350CI engine you should be able to get acceptable drivability from a computer controlled QJet setup. I've gone as far as 230* on a 112* LSA and it still ran the engine pretty good, but I got the definite feeling that was about as far as it wanted to go.