Carburetor question for 66 C-10 with 283

[AslanRules]

I've been reading threads for the past 3 hours and I am unable to find the exact information that I need. So.....here's the deal:

1) 66 Chevy C-10 with a 283 rebuilt by a nice old gentleman.
2) He traded the stock carb (he thinks it was a Quadrajet) for a rebuilt Holley 4 bbl (he thinks it was 650 cfm). I'm pretty sure he used the original intake with adapter for Holley. Carb has electric choke now, but was originally manual (knob on dash).
3) Having trouble starting in AM, as well as re-starting after sitting for 30-60 minutes. Also, cuts out and misses when accelerator depressed......driveable, but annoying.
4) Points, plugs, fuel filter all good.
5) The nice old gentleman told me when I bought it that it needed a smaller carburetor so that it wouldn't miss/surge.

Here's my question(s):

1) Did the 283 come with a 4-bbl or 2-bbl?
2) I haven't closely inspected the carb/intake, but.....is it possible that this puppy was originally fitted with a 2-bbl and that the adapter converted it for 4-bbl usage? Or is that a stupid question?
3) I don't want to buy a new intake, but I think it needs a different carb. I don't mind going with a 2-bbl, if that's what it had originally.
4) If 4-bbl, my reading has led me to lean towards original Quadrajet or Edelbrock 1405 (I want to go back to the manual choke). I also want better gas mileage.....not really into high-performance or hot-rodding. Any opinions would be appreciated.


Thanks in advance for your help.

Randy

[javadoc]

I don't know much, but I'll tell you what I think.

When I first got my '64 it had points. It was a bear to start, and when I installed HEI, it would start like a dream. Well, if it sat for a few months, I'd have to hit it with a little bit of starter fluid, but it really changed the runability for the better. So... I'd suggest you convert to HEI pronto.

As for if the 283 came with a 4bbl, yes they did but I don't know if the trucks came with a 4bbl. I have a 2bbl Rochester on my truck's 283 right now and it runs pretty good (not strong). I'll be ditching my 2bbl in a couple of months when we swap in the 383, if you're interested.

Anyway, that's what I think. I know even less.

[BMSJaX]

I am currently running a Q-jet and I love it. Went from 9 MPG with a Holley 650 4bbl to 13 MPG. It does have the 'surge' or 'sputter' from idle cause it is 'over carbed' but it only requires a jet and rod change, which I am doing this next weekend. Q-jets are divorced or elec. choke but I did hook mine up to a manual cable and after some trial and error and tweaking it works great.
HEI is a must in my opinion.
If you can get the numbers off the front pad(in front of left head) you can probably find out what it came with originally.

[markeb01]

I’m not an expert, but I believe the 4 barrel carb offered on a stock 283 Chevy truck in 66 was a Rochester 4GC. It had a smaller square bore pattern compared to the Quadrajet. I’m pretty sure at that time the Quadrajet was reserved for 327 and larger engines.

The 283 was indeed offered as both 2 barrel and 4 barrel models. As stupid as the concept of mounting a 4 barrel on a 2 barrel manifold sounds, your question isn’t. There were adapters produced to mount 4 barrel carbs on 2 barrel manifolds but for obvious reasons were never very popular. Your manifold is most likely a four barrel version with an adapter to fit the larger carb flange pattern. I’m running a 1405 and very happy with it, but you’ll need to lean out the jets and rods to get best mileage out of it. I’ve developed calculation tables on what worked best for me. If you have interest shoot me a PM and I’ll send you a copy.

If the Holley is a 650, it probably just needs a good tune and jet adjustments to optimize. I wouldn’t necessarily get rid of it just because it’s “too big”. A 650 will work fine on a 283 if set up correctly. You can also convert it to manual choke with a Holley kit if that is preferred:

http://www.jegs.com/i/Holley/510/45-...FSCjiQodkXSuPQ

[geezer#99]

Take some pics of the motor so we can help figure out what you have. Cutting out and missing is not always the carb. Could be your timing.

[MikeN]

A 64 with 283 and 4bbl would not have been a Q-Jet. It would likely have been either an older Rochester design, the 4GC, or possibly a Carter, either AFB or WCFB.

[AslanRules]

Originally Posted by MikeN

A 64 with 283 and 4bbl would not have been a Q-Jet. It would likely have been either an older Rochester design, the 4GC, or possibly a Carter, either AFB or WCFB.

Actually, it's a 66.

I think the gentleman that rebuilt the truck is mistaken about the Quadrajet also. If a 4bbl, it was most likely the 4GC.

MikeN ---- love that seafoam !!!!

Thanks everyone for your help.....keep it coming !!!

3 more questions:

1) Where do I look on the engine for the codes mentioned above?
2) Would I get better mileage with a 2bbl and is it worth swapping the intake, or should I just leave it 4bbl?
3) What's the easiest way to tell if my manifold is 2 or 4 intake without taking off the carb? (rookie question)

Re: HEI ........ I don't really have a problem with points.....I've changed and adjusted many over the years. I would like everything to look stock under the hood, so I've thought about converting the points to electronic using my original distributor and a Petronix kit....just for reliability and so I don't have to monkey with the points anymore. Any opinions?

Thanks,

Randy

[AslanRules]

Originally Posted by javadoc

I have a 2bbl Rochester on my truck's 283 right now and it runs pretty good (not strong). I'll be ditching my 2bbl in a couple of months when we swap in the 383, if you're interested.

Maybe......you selling the intake also?

[Russ65C10]

I have 65 fully loaded C10 with 283 the stock carb was a 2 bbl.

Set up correctly I don't think you notice much difference in mileage between a 2 bbl or 4 bbl. Unless you have your foot in it all the time....

[markeb01]

Theoretically, if the back barrels on the 4 throat remain closed, a 2 or 4 barrel carb should produce the same mileage. In reality, it is generally easier to get better mileage out of a modern 4 barrel, because parts are readily available to optimize lean jetting. With most 2 barrels all you can do is rebuild them, and then get what you get for mileage.

If you’re unfamiliar with the differences between intakes, the easiest way to determine if you have a 2 or 4 barrel manifold is to post a picture. Anybody that knows the difference can easily identify which you have.

If you want to retain the original appearance of the engine/distributor I’d highly recommend the Pertronix kit. I’ve run HEI and Petronix and found both completely reliable. I currently run HEI in my 1960 because it was about all that was available in factory electronic ignition 20 years ago. For cosmetics I’d prefer to have a points distributor with the kit installed. The trade off being, you need to mount a separate coil either on the intake or the firewall. I also have decades of experience setting points, and will never have a car with them again. They are just too much trouble for no benefit.

[AslanRules]

Originally Posted by markeb01

Theoretically, if the back barrels on the 4 throat remain closed, a 2 or 4 barrel carb should produce the same mileage. In reality, it is generally easier to get better mileage out of a modern 4 barrel, because parts are readily available to optimize lean jetting. With most 2 barrels all you can do is rebuild them, and then get what you get for mileage.

If you’re unfamiliar with the differences between intakes, the easiest way to determine if you have a 2 or 4 barrel manifold is to post a picture. Anybody that knows the difference can easily identify which you have.

If you want to retain the original appearance of the engine/distributor I’d highly recommend the Pertronix kit. I’ve run HEI and Petronix and found both completely reliable. I currently run HEI in my 1960 because it was about all that was available in factory electronic ignition 20 years ago. For cosmetics I’d prefer to have a points distributor with the kit installed. The trade off being, you need to mount a separate coil either on the intake or the firewall. I also have decades of experience setting points, and will never have a car with them again. They are just too much trouble for no benefit.

So.....based on that, you would recommend staying with the 4bbl?

So, I'll get the Pertronix kit, and if my problems persist, I'll change out the carb. Should I find a 4GC, or go with Edelbrock? Can I keep my stock intake with the Edelbrock?

Oh......are you saying that I would need a new coil with the Pertronix?

Thanks,

Randy

[markeb01]

If you’re relatively new to the old car/truck hobby, save yourself a lot of grief by delaying the purchase of new parts until you have a chance to learn more about the combination you already have. An analysis of the engine isn’t all that difficult, and may help focus on what really needs attention. Check all the easy stuff first – spark plugs and the plug wires, distributor cap and rotor for carbon tracking or corrosion, fuel and air filters, change the oil and filter, to narrow the options of what may be wrong. The problems you describe could result from anything between bad gas, a vacuum leak, accelerator pump not hooked up correctly, or a dead vacuum advance canister - not necessarily the carburetor.

An inexpensive vacuum gauge will tell you a lot about what is going on. Simply hook one up to a full manifold vacuum source, and observe the gauge when the engine idles, and is accelerated, etc. A Google search for “how to read a vacuum gauge” will provide many explanations of what the indications mean. You could easily have a vacuum leak at the base of the carburetor, or below the adapter, there could be an open port on the carburetor, etc. A timing light can identify whether the vacuum advance in the distributor is working.

When it comes to buying parts, if the truck is going to be a pure stock restoration, I would want to go with original carburetion, on the stock cast iron manifold. Bear in mind any 4GC carburetor is going to be 40+ years old, possibly rebuilt numerous times. Wear on the casting or the throttle shafts can cause leakage, even after an overhaul unless they have had bushings installed. An expensive rebuild isn’t a guarantee of perfect operation. And like the 2 barrel, parts to modify (lean out) the internal operation are not readily available.

If the truck is going to be driven regularly, I prefer the Edelbrock AFB because they are so easy to adjust, and jets and rods are readily available. The rods can be changed by simply loosening two screws and lifting them out of the jets. Jet changes are almost as easy, by removing the upper part of the carb and removing them with a screwdriver. The 1405 can be mounted on a stock cast iron 4 barrel intake, but it will require an adapter, since the holes in the manifold are smaller than the ports in the carb base. Replacing the manifold with an Edelbrock Performer would provide better results if the budget allows.

Note – the 1405 comes from the factory with richer jetting for performance applications than the automatic choke model (1406). In order to maximize mileage, the combination will need to be changed. I believe the 1405 comes with .100 main jets and .070/.047 rods. The 1406 comes with .098 main jets and .075/.047 rods. Changing to at least the 1406 specs will improve mileage. After that it’s time to begin experimenting. If you choose to go this way, take some time and research the carb to see if this is something you’ll be comfortable learning to do.

Holley makes fine carburetors that are very popular, and have some performance characteristics that many prefer. They can also be adjusted for lean operation by changing jets, but it is a bit more complicated for a novice. Unless there is something really wrong with the Holley you have, I would try adjusting (or perhaps rebuilding) it before considering a replacement. Unless the setup is fine tuned to the application, a brand new anything may not perform better than what you have.

Your stock coil will work fine with a Pertronix kit, my comment only applied to the difference between HEI and a points distributor. With HEI the coil is in the cap, with points (or Pertronix) the coil is external.

Any other questions, ask away!

[Russ65C10]

Edlebrocks and Holley's mount up different. If you currently have a Holley and its a direct mount up to your intake then you'll need an adpter (any parts store will have them) and if the Holley is using an adpter you can just chuck it. If you can find a small Q-jet a lot guys are fond of them, they tend to run smaller primary's and get better mileage if you behave yourself ;-)

I don't know about the Pertronix, I went with a Accel pointless distributor and I am pretty sure I started out with the stock coil.

[notsolo]

Originally Posted by markeb01

If you’re relatively new to the old car/truck hobby, save yourself a lot of grief by delaying the purchase of new parts until you have a chance to learn more about the combination you already have. An analysis of the engine isn’t all that difficult, and may help focus on what really needs attention. Check all the easy stuff first – spark plugs and the plug wires, distributor cap and rotor for carbon tracking or corrosion, fuel and air filters, change the oil and filter, to narrow the options of what may be wrong. The problems you describe could result from anything between bad gas, a vacuum leak, accelerator pump not hooked up correctly, or a dead vacuum advance canister - not necessarily the carburetor.

An inexpensive vacuum gauge will tell you a lot about what is going on. Simply hook one up to a full manifold vacuum source, and observe the gauge when the engine idles, and is accelerated, etc. A Google search for “how to read a vacuum gauge” will provide many explanations of what the indications mean. You could easily have a vacuum leak at the base of the carburetor, or below the adapter, there could be an open port on the carburetor, etc. A timing light can identify whether the vacuum advance in the distributor is working.

When it comes to buying parts, if the truck is going to be a pure stock restoration, I would want to go with original carburetion, on the stock cast iron manifold. Bear in mind any 4GC carburetor is going to be 40+ years old, possibly rebuilt numerous times. Wear on the casting or the throttle shafts can cause leakage, even after an overhaul unless they have had bushings installed. An expensive rebuild isn’t a guarantee of perfect operation. And like the 2 barrel, parts to modify (lean out) the internal operation are not readily available.

If the truck is going to be driven regularly, I prefer the Edelbrock AFB because they are so easy to adjust, and jets and rods are readily available. The rods can be changed by simply loosening two screws and lifting them out of the jets. Jet changes are almost as easy, by removing the upper part of the carb and removing them with a screwdriver. The 1405 can be mounted on a stock cast iron 4 barrel intake, but it will require an adapter, since the holes in the manifold are smaller than the ports in the carb base. Replacing the manifold with an Edelbrock Performer would provide better results if the budget allows.

Note – the 1405 comes from the factory with richer jetting for performance applications than the automatic choke model (1406). In order to maximize mileage, the combination will need to be changed. I believe the 1405 comes with .100 main jets and .070/.047 rods. The 1406 comes with .098 main jets and .075/.047 rods. Changing to at least the 1406 specs will improve mileage. After that it’s time to begin experimenting. If you choose to go this way, take some time and research the carb to see if this is something you’ll be comfortable learning to do.

Holley makes fine carburetors that are very popular, and have some performance characteristics that many prefer. They can also be adjusted for lean operation by changing jets, but it is a bit more complicated for a novice. Unless there is something really wrong with the Holley you have, I would try adjusting (or perhaps rebuilding) it before considering a replacement. Unless the setup is fine tuned to the application, a brand new anything may not perform better than what you have.

Your stock coil will work fine with a Pertronix kit, my comment only applied to the difference between HEI and a points distributor. With HEI the coil is in the cap, with points (or Pertronix) the coil is external.

Any other questions, ask away!

40 year old trucks, different owners, parts changing can sometimes add strange combinations . I may be under a misconception but I thought I found a 327 dizzy to look the same as 283 dizzy, but 327 has a larger lobe, truck runs, but not well. Another 2 cents.

[AslanRules]

Originally Posted by markeb01

Theoretically, if the back barrels on the 4 throat remain closed, a 2 or 4 barrel carb should produce the same mileage. In reality, it is generally easier to get better mileage out of a modern 4 barrel, because parts are readily available to optimize lean jetting. With most 2 barrels all you can do is rebuild them, and then get what you get for mileage.

If you’re unfamiliar with the differences between intakes, the easiest way to determine if you have a 2 or 4 barrel manifold is to post a picture. Anybody that knows the difference can easily identify which you have.

If you want to retain the original appearance of the engine/distributor I’d highly recommend the Pertronix kit. I’ve run HEI and Petronix and found both completely reliable. I currently run HEI in my 1960 because it was about all that was available in factory electronic ignition 20 years ago. For cosmetics I’d prefer to have a points distributor with the kit installed. The trade off being, you need to mount a separate coil either on the intake or the firewall. I also have decades of experience setting points, and will never have a car with them again. They are just too much trouble for no benefit.

Okay boys, I'm back with the photos. Since I'm new to this forum and probably don't have much photo bandwidth, I posted my photos on MY WEBSITE. After looking at photos, can you tell if I have a 2 or 4 bbl intake?

I made some photos of the engine compartment early in the day (it had just rained, which is why you will see water on the cowl, etc). I wiped the engine down and then drove about 50 miles and shot some more photos. In the 2nd set of photos, you will see oil pooled on the engine, especially on the intake manifold. The oil had sprayed onto the inside of the hood, and when I opened it, it dripped onto the top of the air cleaner. There was also oil on the underneath side of the air cleaner. One photo shows where I saw some pooled oil and air bubbles were coming from around 2 bolts (with the engine running).

Oh.......and I found an unexpected surprise: I'm no expert, but it sure looks like an HEI distributor to me. So.....the plot thickens.

I know zilch about HEI systems......do they need adjustment? do they go bad? etc?

With all the oil leaking, I was wondering if my sputtering could be caused by the fact that the old guy had just rebuilt the engine when I bought it, and now that I am breaking it in, some of the bolts may need to be re-torqued. Just a theory.

So..............see if this makes sense:

1) check engine with vacuum gauge
2) pull all plugs and check gap and check for possible fouling.
3) check ignition spark with my test light
4) adjust HEI ??????
5) change in-line fuel filter
6) adjust or change carburetor
7) re-torque bolts on heads and intake?????
8) or do I need new gaskets????

Any other ideas?

Thanks in advance.

Randy

[markeb01]

You have a 4 barrel manifold. If it was a 2 barrel, the adapter under the carburetor would look like this with the small part bolted to the engine:



It looks like you’re going to need to remove the intake manifold and install a new set of gaskets. It appears the rubber end seals were used, and ruptured during the procedure (a chunk is sticking out).



It then appears it was attempted to seal the leak by smearing silicone on the outside which is never going to work.

The manifold probably needs to come off, clean everything up, and install a new set of gaskets. It is generally recommended to discard both the rubber and cork end seals, and apply a bead of silicone sealer across both the front and rear block rails instead. To verifty this is the problem, run the engine with the hood open and determine if this is the source of all the oil leakage.

The poorly sealed manifold is probably causing both the oil leaks, and the erratic engine performance due to vacuum leaks.

[Rich 5150 69]

Randy before you go any further, you have a four brrl intake with a holley 600 4160 carb, HEI dizzy, but you have a terrible intake manifold leak all the way around, you`ll needto pull the entire manifold, clean the surfaces well, with new gaskets, a light coating of silicone on the intake bolt threads to seal everythng up.

[geezer#99]

One more potential problem. The red wire running to your electric choke coming through the firewall could short out if the insulation becomes damaged. Need to protect it with a grommet.

[nicke]

How are you guys sure it is a four barrel manifold? I only see one picture and it doesn't show the carb or base plate...

[Rich 5150 69]

This pic here you can see the bolt boss in the manifold but its an early manifold for the 4GC carb, smaller bolt patern.

[nicke]

You are correct....

[Rich 5150 69]

i believe you also have the 305 heads on this going by the casting marks on the ends you`ll see a small double bar or H so to speak in the middle of the end of the head at the bottom...Early intake manfold denoted by the by the oil filler tube, you`ll need to put a valve cover breather vent on the left side valve cover for the PCV valve to work on the right side valve cover...

[markeb01]

I was judging based on this photo:



If it were a two barrel manifold the adapter would be a different style.

The plug wires on the drivers side also need attention, especially where they appear to be resting against the exhaust manifold. A few ties wraps can also avoid problems interfering with the throttle and shift linkage.



Uploaded with ImageShack.us

[AslanRules]

Originally Posted by Rich 5150 69

i believe you also have the 305 heads on this going by the casting marks on the ends you`ll see a small double bar or H so to speak in the middle of the end of the head at the bottom...Early intake manfold denoted by the by the oil filler tube, you`ll need to put a valve cover breather vent on the left side valve cover for the PCV valve to work on the right side valve cover...

You guys are amazing !!!!!!!!!!!

Rich,
Yikes !!!!! I have no idea about such things. So, the 305 heads are okay, but I need to add a valve cover breather? Can you elaborate or refer me to a link? Also, how can you tell that's a 600 Holley?

Geezer,
Thanks for the help. I'm going to change the carb to a manual choke after I fix the intake gasket, so that little red wire is history.

Mark,
You da man. After inspecting the engine today, and with the engine running, I pretty much felt that the gasket needed replacing. But the old guy who rebuilt it........well, I thought he knew what he was doing. I hope there's not other major problems lurking.

Additional questions:

1) Which manual choke carb should I put on it? 4GC? Quad? Edelbrock?
Keep in mind that I want the easiest replacement, i.e. compatibility with my intake manifold......and the most reliable with ease of maintenance. OEM is no longer a concern.
2) If you think I need a new intake, tell me......I don't want to have to re-do this thing later.
3) re: HEI ...... do I need to do anything with this, i.e. adjusting, checking for wear, etc? I know about points and condensers.....HEI is greek.
4) Gas tank --- the old guy pulled the tank, broke up the rust with a chain inside, and then used a tank sealer. But he only used one gallon and 2 are recommended for a 20 gallon tank. Am I probably ok here, or should I spend the $200 and put a new one in while I'm in the mood to fix everything?

(Oh......apologies to all you "old guys" out there. I'm an old guy, too......but the guy who rebuilt this was a little older than me......and I don't want to mention his name in case he's a member of this forum.)

Thanks SOOOOOOOOOOOOOOOO much, guys !!!!!

Randy

[markeb01]

If it were mine, I wouldn't replace the carb. It would be a lot cheaper to simply add a manual choke kit, which is a simple bolt on:

http://www.jegs.com/i/Holley/510/45-...FSCjiQodkXSuPQ

What you have is known to fit, and probably works fine, but you won't be able to tell until the manifold leaks are fixed. Unless you're after performance potential I'd stick with the stock cast iron manifold. One nice feature is they almost never warp, which is a risk with used aluminum manifolds.

As for the HEI, in order to have a baseline it would be a good idea to replace the cap and rotor, or at least inspect the contacts for pitting or corrosion. There really isn't any maintenance required unless the area of the centrifugal weights gets really cruddy. You might also want to check the condition of the vacuum advance. It can be tested easily with a timing light. Disconnect the vacuum line to it and plug the line. Idle the engine and check the timing. Connect a hose from a full vacuum manifold vacuum source (or a vacuum pump). If the vacuum advance is working, the timing will advance.

The money I didn't spend on a carburetor or manifold, I'd invest in a new gas tank. If the repair wasn't done any better than the manifold, the tank could be in worse shape than if it hadn't been "fixed" in the first place. Debris in the gas tank can lead to endless problems that can be hard to diagnose. If you do replace the tank, replace the filter again in case anything was disturbed during the exchange.

I'm an old guy, and have observed that competency isn't age related. I've met guys much older than me, and others half my age that know more than I'll ever learn.