Help choosing a carb!!!

[tendy30]

I've had a few mopar guys look at my engine because I am having problems but their advice seems to vary greatly!

My engine is pinging, which we attempted to adjust the timing and it has helped slightly by putting Shell 97 in it. My carb seems to be leaking gas from somewhere and to be quite honest I am new to mopar world, 440 engine and don't know where to start. I also have some smoke puffing out of the oil cap when I step on the peddle so all in all I know I have a couple issues.

I guess the real question is where to start when you are on a limited budget (new baby boy just arrived). Cosmetic's is where I would like to focus but now with the danger of gas pooling near my distributor I am worried about a fire. I've been given some advice to buy a HOLLY Carb but others have said don't go with Holly for various reasons. WHAT CARB sets up best with a 440 engine and what is the maximum cfm carb you can even put on a 440? At this point I am scared to change anything because of the ripple effect. The best case example is when someone tells me to change the carb but says make sure your exhaust is this size, cam is the type, etc etc or you are just wasting money (something along those lines). I should also throw in that I am trying to stay original but was told the Carters carb's are sh*t.

Any advice is greatly appreciated.

If anyone has a spare performance carb they are willing to sell please PM me.

 

[747mopar]

You didn't mention what carb you have or where the leak is coming from. The leak could be something as simple as an incorrect float level, loose hose adapter, etc. I don't think anybody who knows anything will tell you Holley's aren't a good carb the trick is getting the right one. With no real info on what your wanting to do with it or what car it's in I'd say a 750 vacuum secondary for a good street carb but you could probably run a 650 if your not planning on revving it much. I would start with checking your plugs, they should be the color of "coffee with cream", black is rich and anything lighter then "coffee with cream" is lean. I'm guessing it's running lean which can also be caused by a vacuum leak. Where is your timing set? that can cause it as well. If you get the timing set right, the fuel mixure set right (coffee with cream or a little darker), no vacuum leaks and still have pinging then I'd try an octane additive to see if it helps, do you know the compression ratio? Another thing you can do to combat pinging is get the motor as cool as possible, cool air intake, better cooling system, carb spacer, etc. Good luck

 

[tendy30]

747 Mopar,

Thanks for replying.

I am not even sure what carb is currently in it. I believe it's an original rebuilt carb and the leak is somewhere from the left side of the carb when you are looking at it from a steel pin that sticks out.

The floats work fine. I had those tested. The mopar guy who did most of the testing did all the timing and vacuum testing. I am not sure what the timing is set at but like I said he adjust it a couples times and took it for a spin. The pinging calmed down slightly. He did mention that normal vacuum is somewhere between 5-26 (I think). My Charger is getting less than 5 at idle. I believe his final conclusion was that I need a rebuild or get new carb like a Holly. That was input from one guy. Another guy who looked at it suggested something else and I can't remember the name but his comment was to get rid of carter carb for other reasons.

 

[747mopar]

Can you do a comp test? what oil pressure does it run and how many miles are on it.

 

[tendy30]

I'll be honest I am a newbie to the mopar world. Not sure what a comp test is? Would that tell me the oil pressure as well? Mileage is 43,000 miles roughly.

 

[runner4b5]

I don't mean to take over your post, but I also have a carb question I recently put a 499 (400) stroker moter in my 73 runner I put a brand new proform 950 carb witch runs great after it's well warmed up and goes like a sob, however I really miss not having a choke, I would be willing to sacrifice a little performance for a good quality carb that has preferable an electric choke rather than manual. I did pay a lot of $$$ for my proform but I can use it for a future project (Dart race car) I have in the works.Any sugestions would be appreciated. Thanks Dennis

 

[tendy30]

Another question:

I just looked at these carbs. Can I simply swap any one of these carbs onto my 440 the way it stands now and have no problems or will I have problems going from my current Carters 650cfm to a Holley 750cfm or even 800cfm?

My car is simply a street car and I want power off the line. Not interested in top end speed as I would like to keep my license.

Classic Ind. is selling:

4160 series 750cfm for $380
4150 series 750 cfm for $505 (whats the diff btw the 4150 and 4160 series?)
4150 series 800 cfm for $535
4150 series 850 cfm for $565

What other problems or what else will I have to change if I go to the 750 or 800cfm carb?

Thanks

 

[bigmanjbmopar]

I don't mean to take over your post, but I also have a carb question I recently put a 499 (400) stroker moter in my 73 runner I put a brand new proform 950 carb witch runs great after it's well warmed up and goes like a sob, however I really miss not having a choke, I would be willing to sacrifice a little performance for a good quality carb that has preferable an electric choke rather than manual. I did pay a lot of $$$ for my proform but I can use it for a future project (Dart race car) I have in the works.Any sugestions would be appreciated. Thanks Dennis

I have a remand eddy 800 cfm thunder AVS electric choke carb sitting on my bench I can sell you. works fine I'll even throw in the tuning kit with needles and springs and jets. $225 + shipping

 

[99ss]

comp test is a compression test to see how the rings/pistons are.. smoke puffing out the oil cap can be blow by from worn rings or cracked ringlands.. So you perform a simple compression test to see whats going on in each cylinder

As far as which carb.. the bigger the more gas it eats .. if you are not worried about the gas consumption the 800 or even the 850 would be nice... but I am not an expert either..LOL 440 cubic inches can use some air/fuel if the cam and heads/intake permits it so that needs to be considered as well.
crappy heads/intake and conservative cam doesnt need a whole lot of carb

 

[bigmanjbmopar]

tendy30, sounds like you have a small vacuum leak and a carb that leaks gas which may be at the base and just need a new gasket? or the fuel line inlet to carb is not tight? try carb rebuilding places near you before you go and spend $$$ on a new one. Swapping carbs out is easy just make sure you have all the linkage adapters for the application call the store where you are buying from and make sure they know what it's going on so they can match it all up. Some things are so easy you'll wonder why you even asked ;)

 

[ram250098]

Where abouts in Barrie are ya, I could swing by and have a peek I am just down in Cookstown.
AL

 

[coloradodave]

There you go. Some local help. As to the other fella that worked on your car; when a mechanic says that a rebuild or a new carburetor will solve your problem when you have 5" of vacuum, you need a new mechanic. Do you honestly think that Chrysler would have put Carter carburetors on most of it's cars, including the superstock race cars, if they were sh*t? (your word, not mine). As someone else suggested, ask around and find out who has a good reputation for fixing cars and then spend your money with them. A new carburetor at this point will be a waste of money. Hopefully, ram250098 will be able to help you out. Keep us in the loop.

 

[747mopar]

Well, they answered it for me on the compression, 99ss cleared it up. Anytime your having trouble with these things it's always best to check everything before getting the wallet out. I would recommend for any newbie to check out the cfm formulas, once you get a handle on it you'll quickly see why you may or may not need an 850 or a 750. RPM and Cubes is what determines what size you need meaning a difference between topping out at 6,500rpm or 5,500 makes a huge difference on which size you need. I'll find the formula and post it http://www.4secondsflat.com/Carb_CFM_Calculator.html Changing from 5,500 to 6,500 rpm makes a difference of 100+cfm on my setup, if that gives you an idea. Hears another. http://www.carburetion.com/calc.asp

 

[67 coronet]

Well, they answered it for me on the compression, 99ss cleared it up. Anytime your having trouble with these things it's always best to check everything before getting the wallet out. I would recommend for any newbie to check out the cfm formulas, once you get a handle on it you'll quickly see why you may or may not need an 850 or a 750. RPM and Cubes is what determines what size you need meaning a difference between topping out at 6,500rpm or 5,500 makes a huge difference on which size you need. I'll find the formula and post it http://www.4secondsflat.com/Carb_CFM_Calculator.html Changing from 5,500 to 6,500 rpm makes a difference of 100+cfm on my setup, if that gives you an idea. Hears another. http://www.carburetion.com/calc.asp

for a fairly stock motor is cubes x max rpm divided by 3456.round up to nearest carb size.
to the op,5 pounds of vac at idle is bad to say the least.you need to have someone else look at your ride for sure.that guy you are talking to dont know crap.sounds like he may have caused you more problems then he is fixing.

 

[tendy30]

Thanks for the advice.

I just need to clarify about the mopar tech who looked at my car. My descriptions of his diagnosis are probably not accurate when I am quoting things he has mentioned as problem. He comes highly recommended within the area of where I live. I am simply posting on here looking for alternate advice. I think his adjustments to the engine have helped I just can't afford his services right now and need to attempt the work myself, hence my post here. I am doing my homework and will change the carb myself. If I can't fix it my last resort will be going back to him.

Thanks again for all the help guys. I'll see what I can come up with.