Going from a 2bbl to a 4bbl on a 383

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weiand 8008 intake + edelbrock 600 took my car from sluggo to pepe.

still dialing it in, still have oil leak, but it aint coming from the manifold, I can for sure say that.
 
I have been very into these cars since I was 12 years old, went to UCLA for 4 years in engineering and then went through the Chrysler Institute of Engineering, where they sent me to U of M to get my Masters Degree in Mechanical Engineering, rotated through 8 departments before going permanent in Fuel Systems, and worked in Central Engineering in Detroit and California for Chrysler for 10 years. And I now have some 40 cars, mostly C bodies. So I do have some experience since I worked for Central Engineering from 1969 to 1980 when these cars were being designed and built, and I do my best to put out there what I have learned over the years. But I do not have a problem with people choosing a different path than what I suggest, as we all have to make choices based on our circumstances, finances, experience and capability. My goal is to do what I can to help if someone chooses to consider what I have said. That is all I can do. I like to see these cars done well and enjoyed. After one is on this forum for awhile, you learn who you can trust for good guidance. It is something that is earned over time. So please keep up your comments as I continue to learn too, and you might even be surprised how many people actually heed your advice but do not post their results here for various reasons.
I like your post and I have a friend like you, older guy w tons of knowledge, so I have a ?? for you. I bought a 66 Polara ragtop couple years ago and have done lots of upgrades to make it better and safer. Mine is as best as I can tell a base Polara w/383, 727 tranny, 8 3/4 rear, also has 2 barrel carb w/stock cast iron exhaust manifolds w/dual exhaust I have done nothing to the motor besides change plug wires and it runs like a charm. I'm getting to the point where I can start doing wants instead of needs and my friend Bill suggested a 4 barrel carb w new intake manifold for a little more hp. He suggested a carter carb there's a guy he knows rebuilds them and it would be a simplier upgrade. What do you think?

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I like your post and I have a friend like you, older guy w tons of knowledge, so I have a ?? for you. I bought a 66 Polara ragtop couple years ago and have done lots of upgrades to make it better and safer. Mine is as best as I can tell a base Polara w/383, 727 tranny, 8 3/4 rear, also has 2 barrel carb w/stock cast iron exhaust manifolds w/dual exhaust I have done nothing to the motor besides change plug wires and it runs like a charm. I'm getting to the point where I can start doing wants instead of needs and my friend Bill suggested a 4 barrel carb w new intake manifold for a little more hp. He suggested a carter carb there's a guy he knows rebuilds them and it would be a simplier upgrade. What do you think?

View attachment 446435

My answer would depend on what you are seeking - my comments from several years ago applied to helping make a 383-2 bbl perform more like a factory 383-4 bbl package and regarding the torque converter, going to a smaller converter with a higher than stock stall speed compared to a factory 2 BBl converter achieves a much more responsive off the line performance feel especially at lower speeds and regular driving (i.e. the best bang for the buck - and more important than just going from a two bbl vs. a 4bbl carb alone). Because the 383s have a shorter stroke than a 440, it is important to get the 383 into the higher RPM band quickly where torque is maximized (a 440 doesn't need to rev much to achieve maximum torque due to its longer stroke for example so a relatively low stall speed converter performs well as is) at take off from a stop under more regular driving - doing so makes the car feel lighter and more responsive and to me makes it more fun to drive around town. Also, my comments refer only to use of factory parts and not aftermarket ones that could deliver better results than the factory parts such as intake manifolds and carburetors, exhaust systems, etc.

If you want good low end performance off the line and significantly improved top end performance then the more stuff you add to make it more like a factory 4 bbl setup, the better. That includes the 4 BBl carb, dual exhaust with the hp manifolds and even better flowing heads and a rear end ratio of 3.23 rather than the 2.71 ratio usually present in the 2 bbl package cars. If top speed is an important goal, then using a high stall converter will hurt the top speed you achieve and if fuel consumption matters at all use of a high stall converter will affect that quite a bit (reduced fuel economy since the engine revs more around town and because it is so much more fun to do so as well because of the launch feel).

In my view, the factory 383-4 bbl package was designed to please most folks that wanted better performance with a hit to fuel economy whereas the 2 bbl package was optimized for fuel economy and adequate performance.

Regarding carburetors, I have felt that AVS carburetors do not perform well at low speed off the line acceleration and sometimes hesitate/stumble despite a lot of fine tuned adjustments and WOT performance is not so clean much of the time either. Under those conditions, the Holleys were far superior and had better accelerator pump performace as well under those conditions. But those factory carburetors were mostly junk after a couple years because of warpage of the carburetor due to repeated heat/cool down cycles.

Rather than use a factory AVS, I personally am thinking of trying out the new Edelbrock AVS 2 carburetors that have improved atomization of the fuel under all conditions and that is especially important under low speed accelerations to avoid stumbles, hesitation or worse. I just wish they had bowl vents to help prevent prolonged hot starts but that is a relatively minor issue.
 
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My answer would depend on what you are seeking - my comments from several years ago applied to helping make a 383-2 bbl perform more like a factory 383-4 bbl package and regarding the torque converter, going to a smaller converter with a higher than stock stall speed compared to a factory 2 BBl converter achieves a much more responsive off the line performance feel especially at lower speeds and regular driving (i.e. the best bang for the buck - and more important than just going from a two bbl vs. a 4bbl carb alone). Because the 383s have a shorter stroke than a 440, it is important to get the 383 into the higher RPM band quickly where torque is maximized (a 440 doesn't need to rev much to achieve maximum torque due to its longer stroke for example so a relatively low stall speed converter performs well as is) at take off from a stop under more regular driving - doing so makes the car feel lighter and more responsive and to me makes it more fun to drive around town.

If you want good low end performance off the line and significantly improved top end performance then the more stuff you add to make it more like a factory 4 bbl setup, the better. That includes the 4 BBl carb, dual exhaust with the hp manifolds and even better flowing heads and a rear end ratio of 3.23 rather than the 2.71 ratio usually present in the 2 bbl package cars. If top speed is an important goal, then using a high stall converter will hurt the top speed you achieve and if fuel consumption matters at all use of a high stall converter will affect that quite a bit (reduced fuel economy since the engine revs more around town and because it is so much more fun to do so as well because of the launch feel).

In my view, the factory 383-4 bbl package was designed to please most folks that wanted better performance with a hit to fuel economy whereas the 2 bbl package was optimized for fuel economy and adequate performance.

Regarding carburetors, I have felt that AVS carburetors do not perform well at low speed off the line acceleration and sometimes hesitate/stumble despite a lot of fine tuned adjustments and WOT performance is not so clean much of the time either. Under those conditions, the Holleys were far superior and had better accelerator pump performace as well under those conditions. But those factory carburetors were mostly junk after a couple years because of warpage of the carburetor due to repeated heat/cool down cycles.

Rather than use a factory AVS, I personally am thinking of trying out the new Edelbrock AVS 2 carburetors that have improved atomization of the fuel under all conditions and that is especially important under low speed accelerations to avoid stumbles, hesitation or worse. I just wish they had bowl vents to help prevent prolonged hot starts but that is a relatively minor issue.

The 650 AVS2 is a really nice carb for a 383 with a 383 performer intake. I put one in about a year ago. I also put in a 1/2 inch open phenolic spacer under the carb and the helped a bunch with hot start issues. I'd also been told that the AVS carbs do not like a lot of fuel pump pressure so I installed a regulator and have it set at 4PSI.
 
The 650 AVS2 is a really nice carb for a 383 with a 383 performer intake. I put one in about a year ago. I also put in a 1/2 inch open phenolic spacer under the carb and the helped a bunch with hot start issues. I'd also been told that the AVS carbs do not like a lot of fuel pump pressure so I installed a regulator and have it set at 4PSI.
What car is that in?
 
I have been very into these cars since I was 12 years old, went to UCLA for 4 years in engineering and then went through the Chrysler Institute of Engineering, where they sent me to U of M to get my Masters Degree in Mechanical Engineering, rotated through 8 departments before going permanent in Fuel Systems, and worked in Central Engineering in Detroit and California for Chrysler for 10 years. And I now have some 40 cars, mostly C bodies. So I do have some experience since I worked for Central Engineering from 1969 to 1980 when these cars were being designed and built, and I do my best to put out there what I have learned over the years. But I do not have a problem with people choosing a different path than what I suggest, as we all have to make choices based on our circumstances, finances, experience and capability. My goal is to do what I can to help if someone chooses to consider what I have said. That is all I can do. I like to see these cars done well and enjoyed. After one is on this forum for awhile, you learn who you can trust for good guidance. It is something that is earned over time. So please keep up your comments as I continue to learn too, and you might even be surprised how many people actually heed your advice but do not post their results here for various reasons.
Huh....Very interesting and informative post...........
 
The 66 383 has its limitations, as it was only 270HP anyway. The 361 was 265. Chrysler wanted to cancel the 361 long term. Even putting on a 68 or 69 2bbl Intakewould be a big Improvement. The 66 has a really flat Intake,like the 77 400 engine. The 290 HP really ran a whole bunch better. Then The 383 HP was only 40 HP more.
 
I have a 66 Sport Fury with a 66 383 from a Dodge truck that originally was a 2bbl. Previous owner put an Edelbrock 1407 650cfm on it and it runs good, I'm happy with it

If one is going from a 2 bbl setup to a 4 bbl one, to me at least, the goal isn't to just be "happy" with it. The goal should be to be excited about it and revel in the improved performance it delivers in the lower speed ranges such as off the line and part throttle tip-ins. Without going to a high stall converter, you are leaving a lot on the table and missing out on what is attainable. If you just value good fuel economy and smooth/adequate performance there is no need to bother with a high stall converter then.
 
Anyone have a pic of their 2-to-4bbl actually hooked up to the linkages/throttle post-swap for reference? (-on a factory manifold) Thanks!
 
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