telriv Posted January 11 Share Posted January 11 (edited) NTX5467, One of the things you could do is replace the intake with an aluminum one from TAPerformance. Lighter weight=Performance increase. I already have front & rear sway bars in stock. NOBODY makes the correct rear bars which I have in stock. Won't hurt ride BUT increase steering response over & above what you may already have. Tom T. Edited January 11 by telriv (see edit history) Link to comment Share on other sites More sharing options...
60FlatTop Posted January 11 Share Posted January 11 I have "intimate knowledge" in researching the original basis of design and returning mechanical things back by removing the added upgrades and enhancements. My greatest successes have been in doing that. Some instances have been with cars, enough to know that I truly like the feeling of being the first one to have been there. The majority of my work has been done in building operation. The oldest were a couple of 1880s fire houses that still had some hay on the mow (rhymes. with cow). And I am card carrying certified by the US Green Building Council, USGBC. Even my own house has its origins in stones set in place in 1853. All the stuff I have worked on, cars and buildings, meet the design criteria and they all work pretty good. One of my best learning experiences was back in 1972-73 when I thought the Rochester Quadrajet was too complicated for my 430 powered '68 Riviera. The new Holley 750 Speadbore had just come out. I bought one right away, installed it, and learned to repair and optimize what I had. A lot of things I do probably stemmed from that experience. It came to mind right away so it is not too far from the surface of my thoughts. Back in the 1950s and 1960s the GM divisions took a few of the Rochester carbs to their test grounds where they put them through their paces. They thoroughly tested the jetting, metering, and other adjustable characteristics until they got the application just the way they wanted it. Then they painted the carburetor gold and sent it back telling Rochester "this is the one to produce" in gold. I saw 6 or 8 of them on a shelf one time and got the story of how they were sorted out. That is my choice. Now the buildings, I probably would not have stayed in that field but my sense of ironic humor kept me there. 1 Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted January 11 Share Posted January 11 (edited) 8 hours ago, telriv said: Ben, That starter still working OK for you. Tom T. Syre is. 8 hours ago, telriv said: Ben, That starter still working OK for you. Tom T. Sure is, Tom. As is the Mark IV. Ben Edited January 11 by Ben Bruce aka First Born (see edit history) Link to comment Share on other sites More sharing options...
carbking Posted January 11 Share Posted January 11 (edited) With the posting of individual experiences, thought I would jump in here. First, MOST of the units suggested may be made to work, some better than others. But the more important (opinion) criteria here is the familiarity the tuner has with the design of the unit (whether it is a carburetor or fuel injection), AND the availability of parts to the tuner. Personally, I am familiar with Stromberg and Rochester, and very familiar with genuine Carter. I will admit to having resources not locally available to others when it comes to Carter. First, I have custody of the remaining drawings; but I also have custody of the special lathe hand-built for Carter Engineering in 1929 to produce metering rods. So the project is my shop truck. This is a 1968 Ford F-100 to which has been fitted a mostly stock Mustang GT engine. The truck will accelerate from an idle to WOT with no hesitation, and you will never feel the secondaries, just raw power, in 1st, 2nd, and 3rd gears. In 4th, the engine needs to be above 1000 RPM before flooring the throttle. Finished the truck (as far as one ever gets finished) about 25 or so years ago. Not long after finish, I gave a ride to a youngster (25 maybe), and he proceded to give me the ultimate insult He said "I didn't know they had fuel injection for the 390, what brand are you using?" I grinned at him, and said nothing. When we got back to the shop, I opened the hood so he could see the TWO Carter AFB's sitting on top of the otherwise stock engine. Long before cell phones with cameras, but I wish I had one to have taken a picture of his face. Do how's the fuel economy? Funny you should ask. The twin 625 CFM AFB's run straight linkage, that is, both run all the time. When I finished the truck, non-ethanol fuel was readily available. At 70 MPH unloaded, the truck would average 22~23 MPG. Pulling a 16 foot tandem axle trailer with 2 John Deere 400 series lawn & garden tractors at 65 MPH, the average dropped to 16~17. When it became impossible to buy non-ethanol regular locally, I cut new step-up rods to richen the mixture about 8 percent. This dropped the unloaded mileage to 19~21. I had sold the trailer prior to this, so do not know where that mileage would have gone. The truck WAS upgraded to radial-ply tires, and the dogmatic transmission was upgraded to a 4-speed (this modification alone was good for about a 30 percent increase in fuel economy!) And yes, the carbs have been modified All of this was done WITHOUT the use of electronic test instruments, although it is possible that had I not sold the exhaust gas analyser prior to this project that I might have done a little better, don't know. No longer trying to convince anyone of anything (wag more, bark less ), just relating personal experience. Jon Edited January 11 by carbking (see edit history) 4 Link to comment Share on other sites More sharing options...
XframeFX Posted January 12 Share Posted January 12 (edited) 4 hours ago, Aaron65 said: I'm using a 650 AVS2 on my '63 right now. I bought the Dynaflow "kickdown" adapter from Centerville and wired up the electric choke to a switched fuse. After driving it around with my Innovate wideband (I only install it for carb tuning) I ended up leaning it out one step on cruise and power (using the Edelbrock owners guide) and richening up the idle circuit. Usually, I reduce the size of the top idle bleed on the primary cluster by using a ball bearing to close it up a little and opening it back up to size with a pin drill. It runs pretty well, although I don't know if it's worth the extra money for an AVS2; I've had decent luck with the regular AFB-style Edelbrock in other applications. I typically like running the original Carter (or whatever the car comes with), but I went through the AFB that was on the car about five times, and it was both lean all around and inconsistent in behavior. There are some times when you just have to take advantage of a new part that works reasonably well for what you're doing with the car, and that's when I go with the Edelbrocks. Two of my cars have them and the rest use factory carbs. Aaron, so, your 2 paragraphs are helping to join the dots for me. Thank-You for chiming-in, much appreciated! Would that be an Edelbrock AVS2 1906? Can I swap the primary shaft for the switch pitch shaft I set up in the old 1963 AFB? I already know I'll have to use a modern air cleaner with 5.125" hole. I don't have a budget for anything major especially with another "car project" needing to be made mobile. How likely both idle and power circuits are NG in the 3503 AFB? Perhaps NOT the carburetor but something else? Yes, I'm struggling in the tuning department. So I need more analysis tools! A wideband AFR would be sooo nice instead of just a vacuum gauge and reading musical new sparkplugs time and again. Base timing was left at 14° for highest vacuum at idle which is still lousy. Gotta go, Oilers hockey about to start! Edited January 12 by XframeFX (see edit history) Link to comment Share on other sites More sharing options...
Aaron65 Posted January 12 Share Posted January 12 3 hours ago, XframeFX said: Aaron, so, your 2 paragraphs are helping to join the dots for me. Thank-You for chiming-in, much appreciated! Would that be an Edelbrock AVS2 1906? Can I swap the primary shaft for the switch pitch shaft I set up in the old 1963 AFB? I already know I'll have to use a modern air cleaner with 5.125" hole. I don't have a budget for anything major especially with another "car project" needing to be made mobile. How likely both idle and power circuits are NG in the 3503 AFB? Perhaps NOT the carburetor but something else? Yes, I'm struggling in the tuning department. So I need more analysis tools! A wideband AFR would be sooo nice instead of just a vacuum gauge and reading musical new sparkplugs time and again. Base timing was left at 14° for highest vacuum at idle which is still lousy. The AVS2 on my car is the 1906. I wouldn't change the primary shaft, especially since Centerville sells a really nice, easy to install adapter for $40 for the switch pitch. Anything driveability-related could certainly be ignition, compression, or fuel based. I don't use my wideband to figure out idle mixture; I just use a vacuum gauge because the wideband isn't really that reliable at idle. You've probably already covered this, but did you do a cylinder balance test already to eliminate any weak cylinders? 1 Link to comment Share on other sites More sharing options...
XframeFX Posted January 12 Share Posted January 12 (edited) 2 hours ago, Aaron65 said: Centerville sells a really nice, easy to install adapter for $40 for the switch pitch I'm setup for both. Currently using the Dynaflow mechanical linkage (Image). It actuates just prior to WOT. But could add that 1965 kick-down switch after a Turbo 400 swap. I see the #1906 AVS2 has slightly smaller primary bores yet slightly larger secondary bores of my AFB (Primary Bore 1.44" Secondary Bore 1.75"). A little bit of spreadbore? I could re-visit the cylinder balance test, its been a while. Each cylinder had a drop when I pulled sparkplug wires one at one time. But again, like yourself, inconsistent behaviour. Simply put, with the Hood up, behaviour is good! Edited January 12 by XframeFX (see edit history) Link to comment Share on other sites More sharing options...
Aaron65 Posted January 12 Share Posted January 12 (edited) 8 hours ago, XframeFX said: I'm setup for both. Currently using the Dynaflow mechanical linkage (Image). It actuates just prior to WOT. But could add that 1965 kick-down switch after a Turbo 400 swap. I see the #1906 AVS2 has slightly smaller primary bores yet slightly larger secondary bores of my AFB (Primary Bore 1.44" Secondary Bore 1.75"). A little bit of spreadbore? I could re-visit the cylinder balance test, its been a while. Each cylinder had a drop when I pulled sparkplug wires one at one time. But again, like yourself, inconsistent behaviour. Simply put, with the Hood up, behaviour is good! If you switch to an Edelbrock you'll need to use the Centerville adapter (or something like it) because the new carburetor won't have the correct bracket to operate the Dynaflow switch-pitch rod. This is what I'm talking about: https://www.nailheadbuick.com/product-page/special-dynaflow-pass-gear-linkage-kit-for-aftermarket-carbs-57-63-364-401-425 I'd be checking everything else before I bought a new carb, including cylinder balance. You can short each cylinder with a grounded test light by pulling back the boot on the spark plug wires, and then you can watch a shop tachometer or the tach on a digital timing light if you have one. I'd also check compression with all plugs out to see if I were in the ballpark for what a Nailhead should be. You may also want to substitute another PCV valve (probably a NOS one) if you haven't tried that. Some newer ones will cause a funny idle in my experience. My car idled fine with the AFB; the secondaries were inconsistent and lean under power by a fair bit (mid-to-upper 13s). I might go back and give it another shot eventually, but the Edelbrock runs fine, so it's no hurry. I know you've had idle problems, and I can say that my car idles as smoothly as I expect from an old car, so yours shouldn't be too rough. Edited January 12 by Aaron65 (see edit history) 1 Link to comment Share on other sites More sharing options...
carbking Posted January 12 Share Posted January 12 John - if you don't already have it, here are the specs on your 3503s: Carter 3503s specifications Not a complaint, but a suggestion to the website folks: the acceptance of .pdf files by this site would be a terrific upgrade! If not possible for the whole site, even being able to include the .pdf files in messages. Jon 1 2 Link to comment Share on other sites More sharing options...
Ed R Posted January 20 Share Posted January 20 I appreciate you all of the insight from the veterans on these lovely automobiles. I've wanted a 63-'65 Riviera since I was five, finally made it happen this year. The carburetor has been a thorn - bogging down or stalling at pull-away and at times at speed when floored. A retired mechanic rebuilt the carb for me and the problem continued. He double checked his work with no findings. A change to the forward hole in the linkage did improve pull-away but it bogs after a few beats down the road. The accelerator pump is pumping. I just bought myself a Rochester Carburetor manual to improve my knowledge. Ed, '63 401 Marlin Blue 1 Link to comment Share on other sites More sharing options...
Jim Cannon Posted January 20 Share Posted January 20 (edited) Ed, my '63 had a similar problem when I first got it. I traced it down to an intermittent vacuum leak where the carb mounts to the intake manifold. My car has the Carter AFB and it was missing the stainless steel plate between the intake and the carb. Your Rochester did not have that plate, but you can look for a vacuum leak at the base. Check your gaskets, maybe try a double gasket for extra conformance to an irregular surface. Also check proper vacuum advance on the distributor and make sure you are on the correct vacuum port on the carb for your year. Most carburetor problems are ignition problems. Edited January 20 by Jim Cannon (see edit history) Link to comment Share on other sites More sharing options...
XframeFX Posted January 20 Share Posted January 20 (edited) 8 hours ago, Jim Cannon said: Most carburetor problems are ignition problems. Agree, make sure your PCV and ignition is good with timing set for highest vacuum before adjusting 4GC. I have mine set at 14 for now. Spraying carb cleaner at flanges and fittings to find vacuum leaks. Sounds like your idle circuit is not the problem or that too? If not, a test drive after each tweak. Problem before or after Secondaries opening? Edited January 21 by XframeFX (see edit history) Link to comment Share on other sites More sharing options...
Ed R Posted January 21 Share Posted January 21 Thanks guys, I'll report back. Link to comment Share on other sites More sharing options...
EmTee Posted January 21 Share Posted January 21 If it's really a problem with the carburetor, then changing to the stock AFB would be another option. There was a restored one offered on the forum a couple of weeks ago... 1 Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted January 21 Share Posted January 21 ONCE MORE! 😁 'taint the carburetor, folks, it's the GAS. Best fix is EFI.🤪 To paraphrase a packard saying, ask a man who drives one. Ben Link to comment Share on other sites More sharing options...
gungeey Posted January 21 Share Posted January 21 1 hour ago, Ben Bruce aka First Born said: ONCE MORE! 😁 'taint the carburetor, folks, it's the GAS. Best fix is EFI.🤪 To paraphrase a packard saying, ask a man who drives one. Ben So, as a relatively new hobbyist, what I'm hearing is that due to today's gas I can't have a properly running vehicle unless I convert to efi? Wow, count me out. 1 Link to comment Share on other sites More sharing options...
NTX5467 Posted January 21 Share Posted January 21 The current E10 fuels have less "heat" potential in then, due to the addition of ethanol. I understand the optimum air/fuel ratio is about 14.2 to 1, whereas all of the older cars were calibrated for 14.7 to 1 in days past. Which means the calibration can stand some richening of sorts. Using that proportion, about 4% richer to optimize the mixture, most likely. Of course, EFI optimizes for such things (using an oxygen sensor) AND letting the system also control spark timing also helps (in a coordinated fashion), too. The "accelerates well, then bogs past that" sounds like a "power system" that is not working as designed. On a metering rod carburetor, that can be a broken or missing spring under the power piston. On a fixed-jet carburetor, a failed-closed power valve? NTX5467 1 Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted January 21 Share Posted January 21 2 hours ago, gungeey said: So, as a relatively new hobbyist, what I'm hearing is that due to today's gas I can't have a properly running vehicle unless I convert to efi? Wow, count me out. I did not say that!! I said the BEST fix. And , of course that is my opinion! Probably others. FWIW, my 1950 has been sitting under the carport for two weeks or so since last driven. I just went out and started it. No hesitation. Just started. And stayed running. Works for me. I know, not for everyone. My 1992 Roadmaster, my daily driver, has the same system as the 1950. It sits out all the time. Never fails. I like to drive my old car. I DO like it to be reliable. Enjoy Ben 1 Link to comment Share on other sites More sharing options...
jframe Posted January 22 Share Posted January 22 On 1/11/2024 at 4:07 PM, telriv said: NTX5467, One of the things you could do is replace the intake with an aluminum one from TAPerformance. Lighter weight=Performance increase. I already have front & rear sway bars in stock. NOBODY makes the correct rear bars which I have in stock. Won't hurt ride BUT increase steering response over & above what you may already have. Tom T. Tom, have you heard of any hood clearance issues on a first gen Riv with that new aluminum T/A intake? Link to comment Share on other sites More sharing options...
telriv Posted January 22 Share Posted January 22 Mark, Haven't heard of any, although it does look higher. IF there is a problem all you would have to do is mill the top of the manifold to fit under the hood properly with the clearance as nec. Tom T.. 1 Link to comment Share on other sites More sharing options...
NTX5467 Posted January 22 Share Posted January 22 Which would decrease the plenum volume and possibly cause other drivability issues or move the power band upward. There apparently is a dimension between the base of the carburetor and the bottom of the plenum that is important for best performance off-idle and WOT. A thick OEM-style insulator/spacer can make a difference, as I discovered. Going .25" the other way would make things worse. Lots of little things go into the manifold designs. Recently, I've seen a few videos about presenters cutting out the pad holes to make them larger and connected frt to rr. Plus how much better the changes made the cars run afterward. Even allowing a square bore carb on an original, modified, spreadbore manifold. Even connecting the "holes" on a 2bbl intake! NTX5467 Link to comment Share on other sites More sharing options...
RivNut Posted January 22 Share Posted January 22 Here’s what Russ Martin has to say about carburetors and intakes. In the last sentences, he says don’t use manifold spacers (between the heads and the intake) but he mentions spacing carbs away from the manifold. https://www.nailheadbuick.com/induction-carburetion Link to comment Share on other sites More sharing options...
XframeFX Posted January 22 Share Posted January 22 5 hours ago, jframe said: Tom, have you heard of any hood clearance issues on a first gen Riv with that new aluminum T/A intake? 4 hours ago, telriv said: Haven't heard of any, although it does look higher. I examined a casting this week and appears stock height. I was scrutinizing other attributes such as ports, all NPT and location for the throttle dashpot. The casting has provision for dashpot bracket but can't be correct for both square and spreadbore? Link to comment Share on other sites More sharing options...
OldGerman Posted February 14 Author Share Posted February 14 I'm just in progress of redoing my original Rochester 4GC the second time on my 1963 Riviera. I did it first time in 2017 and the car ran fine except of accelarating on road climbs (fuel starvation/hesitation in accelaration). That could be related to a not properly working power system/power valve on the primary carburetor side. It feels a bit sticky. But my question is about the Main Metering jets. The Chassis Service Manual provides some specs for the Riviera (4700) Carburetor # 7023040: Production jets should be .053" & .076" wheras I found .052" & .080". So, not a big difference in size. Unfortunately my carb ID-tag was missing, so it can be any carb swapped in from another vehicle (engine was swapped in history as well) Anyone has his original 4GC Carb main jet size in memory ? Thank you. Link to comment Share on other sites More sharing options...
BulldogDriver Posted February 14 Share Posted February 14 You want the whole 4GC carburetor from a 63? It was fine when I pulled it a couple years ago and it did a cross country trip right before removal. Just pay the shipping. Ray 1 Link to comment Share on other sites More sharing options...
OldGerman Posted February 14 Author Share Posted February 14 1 hour ago, BulldogDriver said: You want the whole 4GC carburetor from a 63? It was fine when I pulled it a couple years ago and it did a cross country trip right before removal. Just pay the shipping. Ray Where are you located ? 4GC is a heavy beast, 6.3 kg. Oversea shipping to Germany !? Link to comment Share on other sites More sharing options...
NTX5467 Posted February 14 Share Posted February 14 As the 1960s and until we got oxygenated fuel in the 1990s or so, the optimum air/fuel ratio was 14.7 to 1 at cruise. A bit less at idle, in the high 13s or so. IF you were chasing max power, then down into the middle 12s. So the specs in the correct model year factory service manuals reflect these things. With oxygenated fuels and the current E10 blends, the optimum air fuel ratio is closer to 14.2 to 1. Which means the engines are effectively running leaner than the 14.7 mixture (at sea level). For the E15 which many seem to perceive we need to be using, the optimum air fuel ratio would be closer to 14.1 or so, I suspect. In prior times when E10 was not the "national fuel" of sorts, if one jetted up to approach the 14.2 a/f level, it could mean that if normal E0 fuel was used, the resulting mixture would decrease fuel economy a bit. Of course, EFI would compensate for these things automatically, plus altitude issues. The computerized "Carb Cheater" device, being a computer controlled variable vacuum bleed, would need a carburetor with an intentionally-too-rich calibration to work to its capabilities, I suspect. As that device needs to have an oxygen sensor installed, why not just go ahead and install the oxygen sensor and then add the EFI system to it for best drivability and fuel economy? Using one of the fuel sumps to still use the existing fuel lines and sending unit, if enough underhood space can be found. The OTHER observation about using E10 fuels is that it can dissolve the solder used around the sealing balls on the drilled passages of earlier carburetors which are sealed on the external part of the carburetor. In many cases, emptying the float bowl onto the intake manifold of a hot engine. BTAIM Just like being single or getting married, EACH side of that discussion has benefits and other things to deal with. Just depends on which set of "+" or "-" items you want to deal with . . . Enjoy! NTX5467 Link to comment Share on other sites More sharing options...
XframeFX Posted February 14 Share Posted February 14 (edited) 11 hours ago, OldGerman said: I'm just in progress of redoing my original Rochester 4GC the second time on my 1963 Riviera. I did it first time in 2017 and the car ran fine except of accelarating on road climbs (fuel starvation/hesitation in accelaration). That could be related to a not properly working power system/power valve on the primary carburetor side. It feels a bit sticky. Frank, you having a '63 Riviera, you'd have a Bendix multi-vac Power Brake Booster. Did you ever test if it holds vacuum? Maybe I'm one step ahead of you? Typical Riviera, the same issue has to be dealt with 3X. For my third attempt, I purchased an aluminum intake that will allow more carburetor choices. It came from the same place as your Timing Chain, T/A Performance. Make sure it's their spreadbore. version. Package was about 8 Kg. Warning, say good-bye to your pancake air cleaner if you switch to a more modern carburetor unless you modify it as one member has done. Edited February 14 by XframeFX (see edit history) Link to comment Share on other sites More sharing options...
OldGerman Posted February 14 Author Share Posted February 14 John, Thank you for the brake booster hint. I think mine is a Morain Booster (with the external vacuum canister located on the inner fender). I had it rebuild by Booster Dewey a while back, but not much miles on it since then. So I'm confident it holds vacuum. Before that I had a "his" noise when standing at a red light with the foot on the break pedal. As long as possible, I would like to keep carb and air cleaner original. I'm not looking for extra power, but want to gain the maximum of what is still possible with the original setup and the existing deterioration of all components involved. I'm a cruiser, no racer, but I would like to bring back a little bit of it's former performance. Best Regards, Frank 1 Link to comment Share on other sites More sharing options...
BulldogDriver Posted February 14 Share Posted February 14 4 hours ago, OldGerman said: Where are you located ? 4GC is a heavy beast, 6.3 kg. Oversea shipping to Germany !? Stateside in North Carolina. If you come up with a way to include it into something coming your way, let me know and I’ll ship there. Ray 1 Link to comment Share on other sites More sharing options...
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