For anyone who might remember the 305, I've blown it up, and moved onto a 350.
Edelbrock 1406 carburetor, Holley Intake Manifold, stock everything else.

For the most part it is running well, I got it up to 110-120 on the freeway yesterday, and it felt like it was still accelerating.
But my problem is the initial acceleration. The 305 had great torque, and when stomped on from a dead stop, would almost "take a breath" and then just start screaming. That engine could hold it's own against a lot of cars, until they caught up, and beat it. But the launch was good.
The 350 however doesn't really accelerate quickly. It takes it's time, and really hauls *** in terms of top speed, but it doesn't launch well. It doesn't even do the "taking a breath" thing that I liked about the 305. It just starts to go when you floor it, and goes equally as fast at about 1/2 throttle, or 3/4 throttle. There isn't a difference in launch speed.

It was reccomended that I post this question here too, so here it is.

I know there are some carburetor geniuses in here!

Thank you in advance for any help.
-Chris

If I had to guess from your limited information. It sounds like you might actually need to advance your timing or possibly you might have the vac. advance either not hooked up or hooked up wrong. If it's not stalling out or stammering it's probably not the carb. Timing makes a HUGE difference on the initial acceleration.

Does the 350 have a larger than stock cam shaft? maybe a little too big? Did the 305 have a stock or small camshaft?
Is the torque converter the same? Exactly what holley intake manifold do you have?

Yes, the 350 has a larger than stock camshaft. However, I bought the engine almost fully assembled, so I cannot tell you the model number. I was told it was by Comp Cams, but I cannot verify. It's supposed to be a mild cam. I suppose it could be too big, the guy I bought it from is a really old school hot rod guy, so I'd hope he knew what he's doing. His cars seem to run great. Yes, it's the same torque converter. As for the manifold, it's one of the Street Dominators, I think 300-48.

The vaccuum advance is running from the passenger side vaccuum port on the carb to the distributer.

I think I've got the timing at about 6*, would you suggest more?

(It was at about 12, but I lowered it, and it seemed to help a bit)

your setup sounds very similar to mine. I wish I knew what cam was in yours. I have the comp 270 h-10. I have 58cc heads though. I seemed to loose some low end torque too. As far as I know the camshaft that was originally in my 350 was stock. My camshaft's power range is 1800 to 5200 rpms I think. Make sure you get headers though. Comp said that they were recommended. I don't have my full exhaust on yet, but once I put the headers on it seemed to be an improvement. 6* seems a little low. I don't remember where mine is exactly. It's high though. I'm thinking 15ish but I'm not sure. It runs good, doesn't overheat and from what I can hear it's not detonating. I know I set mine at 10 at first and it ran like crap and didn't want to idle.

I want to get headers for sure, but the budget at the moment doesn't allow. I'll definately let you know if I see an improvement with them. At the moment, I'm running straight pipes through the stock manifold. I've since set it back to what I think is around 12, and it's not from what I can tell, it's not knocking, (although I do get a very regular ticking out of the engine, which I'm hoping isn't the valve train) but if I go higher than that, it sounds like it wants to stall. Right now my engine runs at about 240* which I know is extremely high, but it has boiled over yet, and I do plan on getting a dual core radiator for it in the future.

My project car IS my daily driver!

-Chris

mine rarely gets over 190

Are you turning the distributor counter-clockwise to advance the timing?Sounds stupid to ask you but I have never had a motor want to stall as I added initial timing...usually revved up.Now if you are turning it clockwise and retarding it that statement would make sense.And the fact that it runs that hot (240..ouch) screams retarded timing as well..with no more info from you.Not trying to doubt you..just wanna understand better so maybe I as well as others can better help you.

onebad82z:

It does it either direction I go. Clockwise it revs higher, and higher, until it hits a point where it idles really low, and sounds bad, so I've got it just under there. Counterclockwise slowly cranks down, and down until it also stalls.

When I use a light to time it, if I'm looking at the tab from the drivers side fender, the timing mark heads away from me (towards what would be the top of the timing tab from my POV) as I advance the timing.

Sounds like you are going the right way..but way overadvanced if it revs,revs,and then starts to run bad at idle.That is some seerious spark knowck at idle.Try setting it at 10 BTDC degrees with the vacuum advance unhooked and plugged.Then hook up your vacuum advance to a full manifold port on your carb.Try that first..see if it gets any better.

This may be a stupid question, but I'm serious; Should I let the car warm up to temperature before I begin adjusting?
I've been waiting for it to cool down, because my intake and carb get really hot (since I need a better radiator) and I don't want to risk burning myself more.

I'm thinking this may be a problem, now that I think about it.

Car HAS TO BE fully warmed up to operating temp before ANY adjustments to carb or timing are made.

What an idiot!

Thanks a lot man! I'm going to give that a shot now. (I guess this also explains why my idle gets so looooow when the car heats up!)

Someone should really take this car away from me before I hurt myself...

The only way you would be an idiot is if you didn't know..any didn't ask.Learn from your mistakes...it's how I got here..lol.

Try that (warm it up and play with settings) and get back to us.

alright...

Here are my findings.

I drove the car around for a little while to warm it up, cruised, did a little hard acceleration, and drove it home.
Re-adjusted the idle while it was still running, and shut it off.

Removed the air cleaner, and unplugged the vaccuum hose, put a cap on the distributor vaccuum canister, and on the carb port. Then I loosened the hold down bolt for the distributor.

Hooked up my timing light, and re-started the car. Adjusted the timing to 10*, and re-bolted the hold down. Then I turned the car off again. connected my vaccuum hose to the distributor, and then unplugged the other vaccuum port on the carb, and tried it there. Screwed on the air cleaner and started her up.

The car started, and dropped RPM's at a very linear level, until it stalled. Started it again, same story. So, I held the gas a bit to keep it running a took it around the block. The drivability was terrible, and the acceleration was worse.

So I took it home, re-routed the hose to the port it's supposed to be on, and it started up real strong, a little bit of a search at the idle, jumps around a bit, (it always has... I don't get it)

So I take it on the road, and floor it.

the RPM's shot up to about 4000 as the car launched forward, it shifted, dropped to about 3000 and worked it's was back to 4000 very quickly. I now let off the gas because I was doing 45 (the limit here) I didn't feel as fast as I used to go, but it sure got to speed faster, so I'm very pleased. It's obviously doing somewhat better than the 305, so at least it wasn't a bust!

So I tried it 3 more times just to make sure It wasn't a fluke. Now I'm on 1/4 tank! The car gets good milage when I drive like my gramma (which is usually) and now it's a bit speedy too!

I think I'm still going to get a new ignition for it, and probably a new balancer, because I think this one HAS slipped. But even then, it makes me proud!

What gears you running?Stall?Are these stock?Unknown cam,small stall and high gears (more than likely) will make it slow even if it sounds like its flyin'!

But the initial problems seem to be solved?

Stock converter and gears that an 84 SE comes with.
But yes, the initial acceleration is at, or exceeding where I used to be.

So does that mean large stall and low gears makes you fly, and sound like you're going slow?

lol...no..they will actually make the car faster as they allow it to run in the cams powerband easier.It won't sound slower though.

So when I upgrade my rear-end to limited slip, what gears do you reccomend?

What trans do you have?Do you plan to stay with it?What is the main use for the car?Main street car..daily driver...street/strip toy...weekends only?

I've got the 700r4, It's been rebuilt once, but I plan on getting it rebuilt again, with a shift kit. I would like to keep thi s one. The car is a daily driver in the spring-fall, but I'd like to be able to have some street fun, and maybe throw it down the track every once in a while.

I would recommend 3.42's.

Any opinions on those Vigalante converters? They're supposed to "multiply torque and HP"
A brand/stall speed you think is good? Good with this setup?

Some of my wires had burned up on my exhaust manifold, so I changed those, and it helped the idle stability, though it still surges and drops. And it seemed to help the acceleration as well.

I had a vigilante in my 3600 Vigilante in my LS1, made a huge difference. I wouldn't go anywhere near that big in a basically stock thirdgen though. And gears, i would recommend 3.73's.

You might try re-tuning the carb with a tach and vacuum gauge. With the car running hot, there's always the chance you could've bumped something during the swap, and it's running lean.

You might want to also check your plugs to make sure they are not looking fouled up or anything. That's a good indication of your timing and fuel metering being decent. And also a good way to make sure all your wires are firing.

And if you want that 700r4 to last any time you've gotta get that temperature down or get a good tranny cooler. I'd also get a tranny temp gauge to see how hot it's getting. Those tranny lines to cool it come from the radiator which in your case is getting pretty hot. 700r4s don't like temps much above 200 for very long. And they are not cheap to re-build.

Would a tranny cooler be separate from the radiator entirely?
I don't have A/C so I could probably fit one in front of the radiator, correct? I'll have to look it up. Thanks for the advise though. I did hear that heat is the No. 1 tranny killer, and as this is my Daily Driver, that's definately something to look into.

stupid question.

is there any chance there is some mechanical advance,
at idle?

the reason I ask is,
timing should not jump around at idle.

mechanical advance should not have started.

if using "ported" vac signal, the port should be at
low vac by design, therefore, not started to advance

if using manifold vac to the dist,
advance should be 'full in' at idle, and not junping, note,
this can be a 'system' problem with modded cars.

It's not the actual timing that is jumpy, it's the engine rpms. You can hear it surging, and dropping, and see it right along on the tach.

UPDATE:

Today I hooked up my Trans Cooler. I went with the Hayden Ultra-Cool Trans-Cooler, part no. 405. It was 39.99 at .Murrays Hook up was a breeze! It said not to cut the trans fluid hose it came with, but to run it in series with the radiator, I did anyway. It didn't leak during the initial warm up for my fluid check. (Needed 2 extra quarts? Is that normal?) And didn't leak throughout driving today either.

I would definitely rather pay $40 now, then pay hundreds later because I burnt out my trans, so thanks again for the advice.

how does that tranny cooler work? Anyway you could put a temp sensor in it? I've been thinking about adding an extra cooler

By just feeling the hoses going to, and coming from the unit; you can certainly feel a difference. The return hose is cooler than the sender. As far as a temperature reading, I don't have any probes or thermometers of the like, so I wouldn't be much help in that. I do plan on getting a couple of new gauges within the next couple of weeks because my oil pressure gauge died, and the rest are unreliable. So I'll update when that happens.

I've been interested in putting an after market cooler on mine, but didn't know how much of a difference it would be

think we have drifted off topic here???

I'd be cool with starting a second threat about transmission coolers to see how much of a difference there is in the actual tranny fluid.

Yes, this is tranny forum stuff.

Alright! In an update/continuation of this story here's what's gone down.

I overheated terribly. Gauge was pegged out, boiling over. The works.

I was about 150 miles from home, and had to get back, so I drove the car 30 mph the whole way, on the freeway, at 3:00 am. Replaced the radiator, flushed the system, got the cooling under control, so now with the trans cooler, and the new 3 core radiator, I'm set.

But the idle is still messed up.
It has an idle of about 800 in park, and will surge and drop all day.
It sounds like I'm doing it purposely. It's like I'm just tapping the gas over and over again while I'm coasting. Vroom! drop... Vroom! Drop...

I've adjusted the IMS on my Edelbrock 1406, and I've got it set to their specifications. I have it running as high of an RPM as it will run with just the gas screws adjusted (set my idle with the air screw first), and then backed down 20% of a turn. I don't have a computer anymore. I have my EGR blocked off.

When I'm at part throttle (Think parking lot - almost no acceleration) it's surging and dropping like mad! And then if I get on it, it's fine. I thought it might be the distributor, but would this problem be fine at cruising speeds?

I'm running brand new Bosch wires. AC Delco plugs (about 3 months old) Recycled distributor - vaccuum advance.

I recently hooked the PCV system back up, but it was doing this before that.

The full manifold port on the carb IS blocked. The dizzy is on the other one.

The oil was just changed about 600 miles ago. 10w30 (trying to clear up a tick)

I don't know where else to look.
Any ideas? You guys have been very helpful.

-Chris




(I'm sorry if this isn't carb related.I just figured it might be, and why open a new thread?)

I've seen that with ported vacuum advance, where you have to open the throttle blades up to the point that you're almost uncovering the ported port, which gives the advance just a little signal, but not quite enough, and it gets into a surging cycle.

Try manifold vacuum to the advance, readjust the idle speed and mixture, and see if that straightens it up.