I am going to do a 2V carburetor and have not decided on which one to use. I want to pick up some performance, but don't want to kill driveability. Those of you who have done the conversion, which way did you go? Would you do it again? Would you switch from one carburetor to the other?
Which carburetor? Autolite 2100 or Holley 5200??
- Thread starter jimlj66
- Start date
Howdy Jim:
There are lots of opinions on this subject here on this forum. There are also lots of shared experiences. Before you will get any specific, practical insights, you will need to give more information about your goals and intended out come for your vehicle. I could offer you lots of info on the 2100, but little on the 5200. The big generality is that the 5200s offer improved driveability, better MPG, and a slight increase in performance. However, a 2100, properly sized and tuned, can give all of that and more of a power increase. Some have found the 5200 hard to tune and finnicky.
The 2100 came into use in the 1957 model year and remained until 1974 when it was upgraded(???) to the 2150. The downside of the 2100 is that they are no longer in production. They are only available as rebuildable cores or rebuilt. Since they were the standard carb on millions of 221s, 260s, 272s, 289s, 292s, 302s, 351s, 352s, 390s & 429s finding a good core is fairly inexpensive and relatively easy. Rebuild kits are easy to acquire, and the 2100 may be the easiest ever carb to rebuild. They are available in eight sizes ranging from 190 to 424 cfm. The 2100s are fairly sturdy, lighter than a Holley 2300, have no gasket lines below the fuel level, and are fairly easy to tune.
Both will require a '68 and later distributor which utilizes a ported vacuum source to work as designed. Both will require adapting the mount, fuel lines, and linkage. And require a non stock air cleaner. Mike's website has dyno info on the 2100s by size and application. I don't recall seeing dyno info on the 5200 but it may also be there. Check it out.
Now, how about some more of your details?
Adios, David
There are lots of opinions on this subject here on this forum. There are also lots of shared experiences. Before you will get any specific, practical insights, you will need to give more information about your goals and intended out come for your vehicle. I could offer you lots of info on the 2100, but little on the 5200. The big generality is that the 5200s offer improved driveability, better MPG, and a slight increase in performance. However, a 2100, properly sized and tuned, can give all of that and more of a power increase. Some have found the 5200 hard to tune and finnicky.
The 2100 came into use in the 1957 model year and remained until 1974 when it was upgraded(???) to the 2150. The downside of the 2100 is that they are no longer in production. They are only available as rebuildable cores or rebuilt. Since they were the standard carb on millions of 221s, 260s, 272s, 289s, 292s, 302s, 351s, 352s, 390s & 429s finding a good core is fairly inexpensive and relatively easy. Rebuild kits are easy to acquire, and the 2100 may be the easiest ever carb to rebuild. They are available in eight sizes ranging from 190 to 424 cfm. The 2100s are fairly sturdy, lighter than a Holley 2300, have no gasket lines below the fuel level, and are fairly easy to tune.
Both will require a '68 and later distributor which utilizes a ported vacuum source to work as designed. Both will require adapting the mount, fuel lines, and linkage. And require a non stock air cleaner. Mike's website has dyno info on the 2100s by size and application. I don't recall seeing dyno info on the 5200 but it may also be there. Check it out.
Now, how about some more of your details?
Adios, David
Hi David.The 2100 was also stock on the 360FE engine.Thats what came stock on my 1974 F100.Used it on the 302 that replaced the 360.Worked GREAT with no retune.Leo
Thanks for the input.
The car is a '66 Mustang with cali emissions. C4 transmission, as far as I know stock everthing. 96xxx miles. I know the engine has been apart. It had a rod knock and I put new rod bearings in. It had .010 under bearings in it so at least the bottom end has been into.
What I want is good drivability, added performance. Decient fuel mileage would be a plus. This car is a weekend cruiser and won't see more than a few thousand miles a year so fuel economy is not my top priority.
I am going to use a '82 head, and while I have it off, I am going to mill for a 2V carburetor, valve job with 1.5" exhaust and mill head for restored compression. Not sure yet what bottom end to use. I have the complete donor car ('82 Merc Zephyr) and will use what is in best shape. I'll use the DSII dizzy. I want to hit a compression ratio that I can use 87 to 91 ish pump gas at 6900' elevation. I don't know what cam to use. This old electrician reading cam spec sheets is like the average american trying to read Russian. I plan on headers, but after reading some of the posts, I don't know if it is worth the cost. Suggestions on cam and headers welcome.
What I want is the fastest, butt kicken V8 eatin car on a $500 budget. If I cant have that, I will throw in a couple extra grand and settle for a nice drivable better performing six, pushing a C4 transmission in a classic weekend driver car.
The car is a '66 Mustang with cali emissions. C4 transmission, as far as I know stock everthing. 96xxx miles. I know the engine has been apart. It had a rod knock and I put new rod bearings in. It had .010 under bearings in it so at least the bottom end has been into.
What I want is good drivability, added performance. Decient fuel mileage would be a plus. This car is a weekend cruiser and won't see more than a few thousand miles a year so fuel economy is not my top priority.
I am going to use a '82 head, and while I have it off, I am going to mill for a 2V carburetor, valve job with 1.5" exhaust and mill head for restored compression. Not sure yet what bottom end to use. I have the complete donor car ('82 Merc Zephyr) and will use what is in best shape. I'll use the DSII dizzy. I want to hit a compression ratio that I can use 87 to 91 ish pump gas at 6900' elevation. I don't know what cam to use. This old electrician reading cam spec sheets is like the average american trying to read Russian. I plan on headers, but after reading some of the posts, I don't know if it is worth the cost. Suggestions on cam and headers welcome.
What I want is the fastest, butt kicken V8 eatin car on a $500 budget. If I cant have that, I will throw in a couple extra grand and settle for a nice drivable better performing six, pushing a C4 transmission in a classic weekend driver car.
Howdy Back Jim:
"What I want is the fastest, butt kicken V8 eatin car on a $500 budget." LOL!!!! Don't we all. Good one Jim.
Either carb will do you. For ease of tune and set-it-and-for-get-it reliability, I'd go with a 1.01 or 1.02 2100 from '62 - '64. They are rated @245 cfm. They make for great all-around carbs; good throttle response and mileage, and a nice increase in power. And you could step up to a 1.14 size rated @ 300 cfm.
Your build plan sounds good. You said your engine is a Calif/Em engine. I'm guessing that you already know about the large OEM dish pistons in that short block? Something to consider when choosing. IF you decide to go with the '66 block, you'll likely have to replace the pistons if the block needs to be overbored, but something to plan for. Your CR goal is right on. What state are you in? Some of the \oxyginated gas formulas in some states seem to be a little down on power. Depending on the cam you select, you may want to up the CR a little to say, 9.2:1 range. That would help with low end torque and mileage. I'm assuming you will maximize the combustion chambers efficiency.
On the '82 block, is it a high mount starter, or a low mount starter block? IF high mount starter, no problem. If low mount starter plan to use the bell, trans from the '82 as well as the engine. What exhaust manifold is on the 82? Is it the typical center dump into a head pipe? or the end dump into a cat converter? Again, no problem if you're going to a header exhaust. Neither the '66 Ca/Em nor the '82 exhaust manifolds make good upgrade choices.
I'm still expecting someone with a 5200 to come along to share the joys of a 5200 Holley/Weber. I know they are here. It would be worth your time to hear from some of them before deciding. However, once you do the carb mounting modification to the log, switching from a 5200 to a 2100/2300 is easy.
On the cam, IIWIYS, I'd call Mike at CI and ask him for advice. There are getting to be more out there with your goals in mind. In general, with a modified log head and a C4 trans, you will want a cam with good vacuum characteristics and a good torque range between 1,500 -5,000. Then you'll need to loosen the torque converter slightly and plan for 3.20/3.25 rear gearing.
Keep it coming Jim.
Adios, David
"What I want is the fastest, butt kicken V8 eatin car on a $500 budget." LOL!!!! Don't we all. Good one Jim.
Either carb will do you. For ease of tune and set-it-and-for-get-it reliability, I'd go with a 1.01 or 1.02 2100 from '62 - '64. They are rated @245 cfm. They make for great all-around carbs; good throttle response and mileage, and a nice increase in power. And you could step up to a 1.14 size rated @ 300 cfm.
Your build plan sounds good. You said your engine is a Calif/Em engine. I'm guessing that you already know about the large OEM dish pistons in that short block? Something to consider when choosing. IF you decide to go with the '66 block, you'll likely have to replace the pistons if the block needs to be overbored, but something to plan for. Your CR goal is right on. What state are you in? Some of the \oxyginated gas formulas in some states seem to be a little down on power. Depending on the cam you select, you may want to up the CR a little to say, 9.2:1 range. That would help with low end torque and mileage. I'm assuming you will maximize the combustion chambers efficiency.
On the '82 block, is it a high mount starter, or a low mount starter block? IF high mount starter, no problem. If low mount starter plan to use the bell, trans from the '82 as well as the engine. What exhaust manifold is on the 82? Is it the typical center dump into a head pipe? or the end dump into a cat converter? Again, no problem if you're going to a header exhaust. Neither the '66 Ca/Em nor the '82 exhaust manifolds make good upgrade choices.
I'm still expecting someone with a 5200 to come along to share the joys of a 5200 Holley/Weber. I know they are here. It would be worth your time to hear from some of them before deciding. However, once you do the carb mounting modification to the log, switching from a 5200 to a 2100/2300 is easy.
On the cam, IIWIYS, I'd call Mike at CI and ask him for advice. There are getting to be more out there with your goals in mind. In general, with a modified log head and a C4 trans, you will want a cam with good vacuum characteristics and a good torque range between 1,500 -5,000. Then you'll need to loosen the torque converter slightly and plan for 3.20/3.25 rear gearing.
Keep it coming Jim.
Adios, David
Thanks David.
I live in Evanston Wyoming. I don't know if the gas around here is oxyginated or not. As for high mount/low mount on the 82, I think it is low mount, but not sure. I'll check when I get back in town.
You said to use the bell/trans from the '82 if I use that engine. I understand the bell part, will my '66 transmission not work with the '82 bell? I'm not sure what transmission the Mercury has in it. C3? C4? C5? How do I tell? I have not had time to do much with the Merc since i got it.
What is special about a '62-'64 2100 over other years?
I'm sure I'll have more questions later
Thanks again
I live in Evanston Wyoming. I don't know if the gas around here is oxyginated or not. As for high mount/low mount on the 82, I think it is low mount, but not sure. I'll check when I get back in town.
You said to use the bell/trans from the '82 if I use that engine. I understand the bell part, will my '66 transmission not work with the '82 bell? I'm not sure what transmission the Mercury has in it. C3? C4? C5? How do I tell? I have not had time to do much with the Merc since i got it.
What is special about a '62-'64 2100 over other years?
I'm sure I'll have more questions later
Thanks again
Howdy Back Jim:
Q- "will my '66 transmission not work with the '82 bell?"
A- If it is a high mount starter engine/bell your early C4 should work. If it is a low mount starter your '66 C4 will not work.
Q- "I'm not sure what transmission the Mercury has in it. C3? C4? C5? How do I tell?"
A- The C3 will have 13 bolts holding the pan. C3 were very light duty. Used from '74 - '87, mostly behind 4 cylinder engines. The C4 & C5 have 11 bolts holding the pan. The C5s have a lock-up torque converter and were in production from '82 to '86. My guess is that the Mercury line would use a C4 or C5.
Q- "What is special about a '62-'64 2100 over other years?"
A- These were the only years this size was used and only on 260 V8 engines. The 2100/4100 Autolite carbs were designed by Holley in 1957. Another plus of the early carbs is that prior to a production revision in 1964 all Autolite carbs used Holley jets. These early years also used a brass pressed in bowl vent tubes. The down side is that these carbs are getting very scarce. The 1.14 (Would be my 2nd choice) and 1.08 sizes are much more readily available and have all of the same attributes the earlier carbs have- except the Holley jets. 1.14 - 1964 - 1967, 1.08 - 1968 - 1973. Rated @ 300 & 287 cfm. If you hit swap meets start looking for junk cores and rebuilders. They are a good source for jets, as well as other parts.
Adapting an electric choke from later years of 2100 and 2150 is a great upgrade to the earlier hot air choke system. Also know that Holley power valves work fine on the 2100s.
I think Wyoming still has "Good" gas, but I'm not sure on that.
You've got some checking to do. Keep the info coming.
Adios, David
Q- "will my '66 transmission not work with the '82 bell?"
A- If it is a high mount starter engine/bell your early C4 should work. If it is a low mount starter your '66 C4 will not work.
Q- "I'm not sure what transmission the Mercury has in it. C3? C4? C5? How do I tell?"
A- The C3 will have 13 bolts holding the pan. C3 were very light duty. Used from '74 - '87, mostly behind 4 cylinder engines. The C4 & C5 have 11 bolts holding the pan. The C5s have a lock-up torque converter and were in production from '82 to '86. My guess is that the Mercury line would use a C4 or C5.
Q- "What is special about a '62-'64 2100 over other years?"
A- These were the only years this size was used and only on 260 V8 engines. The 2100/4100 Autolite carbs were designed by Holley in 1957. Another plus of the early carbs is that prior to a production revision in 1964 all Autolite carbs used Holley jets. These early years also used a brass pressed in bowl vent tubes. The down side is that these carbs are getting very scarce. The 1.14 (Would be my 2nd choice) and 1.08 sizes are much more readily available and have all of the same attributes the earlier carbs have- except the Holley jets. 1.14 - 1964 - 1967, 1.08 - 1968 - 1973. Rated @ 300 & 287 cfm. If you hit swap meets start looking for junk cores and rebuilders. They are a good source for jets, as well as other parts.
Adapting an electric choke from later years of 2100 and 2150 is a great upgrade to the earlier hot air choke system. Also know that Holley power valves work fine on the 2100s.
I think Wyoming still has "Good" gas, but I'm not sure on that.
You've got some checking to do. Keep the info coming.
Adios, David
mysavioreigns
Famous Member
I'm bumping this because I'm also interested to see what the advantages of the 5200 over the 2100 might be. I put on the 5200 a couple years ago - I wasn't even aware the 2100 could be adapted to the 200ci.
The 5200 I have, though it has been re-jetted, seems to just be finicky. That could be a variety of reasons, however, but it seems that it needs tweaking when the season changes - i.e. one season it will be too lean, then way to rich, without me changing anything. One thing I'd like to try, though, is getting the distributor correctly up to snuff (recurving and a better coil) before throwing another variable into the mix.
Any other 5200 users who have some input?
Good thread
The 5200 I have, though it has been re-jetted, seems to just be finicky. That could be a variety of reasons, however, but it seems that it needs tweaking when the season changes - i.e. one season it will be too lean, then way to rich, without me changing anything. One thing I'd like to try, though, is getting the distributor correctly up to snuff (recurving and a better coil) before throwing another variable into the mix.
Any other 5200 users who have some input?
Good thread
