Carburetor Upgrade Advice

Hello Everyone,

Looking to upgrade the carb on my inline. Everything is pretty much stock on my car. Currently running the original autolite 1100. The compression on my cylinders isn't all the best ( in the 120 psi range). Feel that a carb upgrade in conjunction with boring out the intake a little will help the engine breathe better. Perhaps it will help get the fuel better distributed to cylinders 1 and 6. The cars been running a little rough lately and hesitating. A good tune up and idle adjustments will certainly help, but I feel that it needs a little more. The whole engine could probably use a good rebuild but not ready for that at the moment. Any advice on a good carburetor to upgrade to would be very appreciated. Also, what is a good size to have the machinist bore out the intake? Planning to head to the swap meet at Carlisle, Pa this weekend and check out their carb selection. Thanks in advance.

Get a Weber, very versatile and easy to tune if you understand how all the circuits work and affect each other. I'm currently running a 38/38 DGES (without the choke).

Howdy 65 Mustang:

Are you planning on staying with stock linkage? Distributor? where are you located? Elevation?

Have you checked your initial timing? Are you getting full throttle at the carb when you floor the gas pedal?

There are several good options on carb upgrades but changing one thing seldom works up to expectations. A coordinated plan that covers all the parts of a good running engine is the place to start.

That said, an Autolite 1101 from a '63 or '64 Ford car with a 223 six would be a great upgrade with a stock Load-O-Matic distributor. It will be stock appearing. Linkage, fuel lines, vacuum lines, air cleaner and choke are identical. You'd be going from 185 cdm on your stock 1100 to 210cfm on the 1101. This carb has a SCV to be compatible with your stock distributor. The only mod is to flare out the top of the adapter between the carb and the manifold to clear the larger butterfly valve.

I hope that is helpful to you. Keep us up to date on your progress.

Adios, David

Thanks for the responses guys. Appreciate it. My distributer is pretty much stock, although I did put a pertronix electronic ignition in it. The car is being run near sea level. I do have a whole other inline sitting on my garage floor. The dream is to one day rebuild that and place it in my car. In the meantime, though, I was just looking to attach a larger carb hoping the engine would perform better. Just out of curiosity, what are the pros and cons of a dual carb system versus one larger carb? Also, what about increasing the diameter of the opening on the intake manifold? Thanks again.

Is your installed six a 170? A 200 in your garage? Do you plan to stay with a one barrel when you rebuild your spare motor? A two carb motor would be awesome but will have machining costs and you need to be a pretty good mechanic. What trans do you have?
Do you have a copy of the Falcon Performance Manual? It is very helpful.

Thanks for the reply. The engine in my car is a 200 as well as the other engine I have. Have not considered 1 vs 2 barrel. Any advice? I have an automatic trans currently in car. I plan to put a manual trans in in the future. Have not yet purchased the falcon manual. I definitely will though as it is mentioned so many times in this forum. Sure it's a great one to have.

65 Mustang,

I found myself asking the same question a few weeks ago. I have a stock 200cid motor on my mustang with an Autolite 1100, headers, Duraspark II distributor and ignition, and T-5 transmission. I bought an Autolite 1101 carb and sent it out for rebuild. I will be installing the autolite 1101 carb this weekend. I've been told that the Autolite 1101 is a very nice upgrade over the stock carb. I'll find out in a few days and I'll post how it turns out.

Check out this thread:

viewtopic.php?f=1&t=74552&p=573586&hilit=2100#p573586


Tom

Yes, & while waiting for "Handbook" delivery go to the sponsor of this forum's site - classicinlines.com and preuse the articles there. Untill I did these 2 things I didn't really know what Qs to ask! They both are very informative! These machines R systems & something done to 1 prt effect other prts (therefore need planning to support the whole system - or screw it up).
As David posted - U file a funnel shaped enlargement @ the mounting interface. If interested measures must be taken if doing it w/o removal to assure metal filings don't "go down yer intake". Doesn't play well w/valves, pistons, etc!
Keep talkin…

65 Mustang":2s4gyvfn said:

Thanks for the responses guys. Appreciate it. My distributer is pretty much stock, although I did put a pertronix electronic ignition in it. The car is being run near sea level. I do have a whole other inline sitting on my garage floor. The dream is to one day rebuild that and place it in my car. In the meantime, though, I was just looking to attach a larger carb hoping the engine would perform better. Just out of curiosity, what are the pros and cons of a dual carb system versus one larger carb? Also, what about increasing the diameter of the opening on the intake manifold? Thanks again.

Click to expand...

You should open up the intake to at least 1 3/4 inch if not a little more. Good luck

Tom: Thanks for directing me to that thread. Read through. Lots of good info there.

Chad: Completely agree that the system needs to be considered as a whole. It's probably more than just my carb that is responsible for the mediocre performance. No doubt it also has to do with my low cylinder compression. Been talking about removing the head and having it shaved down a bit for a while. Maybe now is the time. I'll get a 3 angle valve job and put in hardened seats while I'm at it.

Bubba: Thanks for the bore size number. Would increasing to 1.75" while keeping the original autolite 1100 still improve things or does a larger bore size only improve things if you have a larger carb as well? Thanks.

David: Thanks for the info concerning the autolite 1101 upgrade. Could you elaborate on flaring out the adaptor between carb and manifold? Any pics? Thanks so much.

It's biggest benefit is going to be so you can use easily use the bigger carb's or if you go with a 2V to 1V adapter. Though in theory there maybe also a slight improvement even with a 1100 in helping the flow into the log. IE So that the fuel mixture can better make the short turn radius going into the log. One of our site members " Xctasy " uses a coring drill to open them up even larger to about 2 inch. Good luck

Howdy Back;

A good place to start might be to identify which head casting(s) you have. Most '65 castings will be either a C5xx or C6xx. The Casting code is on the top of the manifold, just behind the carb hole. The carb hole will measure 1.5". Once we know the code of the heads you have we can be more specific in advice. Boring out the carb hole from 1.5" to 1.75" Will not have much effect on performance. It will increase the volume of the manifold which could help at higher rpms.

For starters have you maximized your initial spark advance setting? Have you checked to be sure you are getting full throttle when the gas pedal is depressed? Does your engine smoke or use oil?

FYI- the later head castings have several advantages over a C5 or 6 casting. They have a 1.75 carb hole, bigger valves, larger intake tract volume and induction hardened valve seats. You might want to consider finding a D7xx or later casting to build while you continue to drive with the stock engine. Once the newer head is complete the cars down time will be limited to swapping heads. A newer head will save the cost of bigger valves and installing hard valve seats into the old head. Just a thought.

Adios, David

What year of manufacture is the 200 in your garage?

bmbm40 Were you asking me about the year, If so that's an 1981 up Fox chassis 200?

65 Mustang":q8sg8k6u said:

Hello Everyone,

Looking to upgrade the carb on my inline. Everything is pretty much stock on my car. Currently running the original autolite 1100. The compression on my cylinders isn't all the best ( in the 120 psi range). Feel that a carb upgrade in conjunction with boring out the intake a little will help the engine breathe better. Perhaps it will help get the fuel better distributed to cylinders 1 and 6. The cars been running a little rough lately and hesitating. A good tune up and idle adjustments will certainly help, but I feel that it needs a little more. The whole engine could probably use a good rebuild but not ready for that at the moment. Any advice on a good carburetor to upgrade to would be very appreciated. Also, what is a good size to have the machinist bore out the intake? Planning to head to the swap meet at Carlisle, Pa this weekend and check out their carb selection. Thanks in advance.

Click to expand...

You really won't get a good tune with that low of compression, extra initial advance, should help, though.

65 Mustang":16hbd0oe said:

Any advice on a good carburetor to upgrade to would be very appreciated. Also, what is a good size to have the machinist bore out the intake? Planning to head to the swap meet at Carlisle, Pa this weekend and check out their carb selection. Thanks in advance.

Click to expand...

I'm in the same boat and agonized over which carb to get. I finally decided on a 2V Weber and boring out the log opening to fit the Weber 2V adaptor plate that Classic Inlines used to sell (member Does10s is currently selling the inventory and still has these adaptors). The procedure is spelled out in detail on the Classic Inlines tech section.

I however have a large log '78 head with the flat log so its easier to adapt than the earlier round log head.

You may want to keep your eyes open for a later large log head at that swap meet... increased flow in those...

I have a large log head from a 69 Mustang 250 if anyone is looking for one.

bubba22349-I was asking the original poster what year his 200 was. Your 81 is exactly what he needs. That is a good one with the big bell block for bolting up a T5.

Yeah that picture is one of Xctesy's! I only wish could have gotten one of those blocks too (missed out on a locale one about a year ago). Have all of the top end parts like those, they are the ones I have listed for sale now.