600 cfm carb right for the 304??

OK so I have an edlebrock 1405 carb on my CJ5...... I am just starting to get into everything, this is an issue with driveability at the moment. My main question is if the 600CFM carb is too much for the 304? It seems to be really RICH throughout the usable range of rpms. Down low it is OK, but if I get on the throttle it is RICH... Also I noticed on a side slope one direction is good, the other and the carb floods out....

I removed the carb tonight, noticed I have the stock intake manifold and only an adaptor plate for the 4bbl carb. I cleaned all passageways and adjusted the float height to 7/16", the two were not equal.... My best thought was to find an original 2bbl and put that on there...?
I have lots of experience on multi bank carbs on motorcycles so this is actually pretty simple. I just need to find a source for jets locally, would Napa have them?

Kent

 

I have a 500 cfm carb on a edelbrock torker II intake just get the jetting correct and it should run great with good gas mileage as long as you keep your foot out of it. I had a 650 on there and it ran way too rich all the time fouled out my plugs, it didnt go well. the figures I came up with a 525-550 cfm carb would be a great match for the 304 with a torker manifold. what type of manifold you are planning to run? because if you want to go 4bbl I would not use a stock manifold. if you want to go back to 2bbl stock is good but there are still better ones.

 

At this point I am just wanting to get things running well. If I need to replace the carb with a 2bbl to do so I will. I am not after "performance" mods on the motor, I think it is plenty for what I want to do with the CJ. After test driving last night I believe the float level made a big difference as it was too high on one side. I need to drive the same side slope as before to know for sure.

Kent

 

A carburetor that size is more likely intended for 350-400cid engine out of the box, so on a 304 it will need some tuning. I don't know anything about the AFB/Edelbrock, but I would suggest that you get a book and read about tuning it. Typically, an oversize carburetor has low vacuum at low speed, and poor fuel control and atomization at low speeds. Howerver, 600CFM isn't hugely oversize for a 304, and with the right jetting etc. it should be ok. Not optimal, but fine.

I also recall that the Edelbrock can be fitted with spring loaded needles for off-road, but that's usually intended to stop flooding when you're bouncing. Flooding on sidehill would suggest that your bowl level is set too high, or that the Edelbrock has problems with flooding the vents (don't think that's true - there may be other things to do to set the carb up for offroad though).

 

Rereading your original post, if you have a 2V manifold and running an adapter, you may as well sell the 4V and get a Motorcraft 2V, or else get a 4V manifold. The early AMC 360 4V manifolds have the square pattern, though the later manifolds use the unique Motorcraft 4350 spread-bore pattern (avoid those).

I'd just get a 2150 from that guy on ebay, and sell the AFB. You can probably get most of the price of the 2150 by selling the AFB. The 2100/2150 is excellent offroad, and a good carburetor (for a carburetor).

More - isn't the AFB a needle jet carburetor? Not sure where you would get needles and jets except from Edelbrock.

link - http://motors.search.ebay.com/_W0QQsassZehrmannmp

 

I had a similar situation. The PO had put a Holley 650 on my 304 via a adapter. The secondaries weren't even hooked up so I guess I had a 4bbl carb acting like a 2bbl. When I did a valve job I purchased a Holley 7448. It is a 350 cfm replacement for the Auto lite 2100. I got it from Summit Racing and sold the old Holley. I really like it. BTY Holley doesn't recommend anything larger unless modifications like a cam or headers have been made.

 

If you stick with the 4v, I have a square bore manifold off a '75 360. I also have the MC4300, but it needs a major rebuild.

 

Thanks for all the info guys!!

I believe my short term solution is to play with the carb I have on there, as of now it runs OK at/or below 1/4 throttle. Then in a little while I'll get a good 2bbl carb and sell off the Edelbrock. It all comes together now that I have all the info about this Edelbrock being a 600cfm carb and I have no major mods on the motor.

Kent

 

Dan, what 500 do you run on your V6? I'm currently running a 600 Edelbrock and it doesn't work the greatest. Way to rich, won't idle down very low and floods going down steep hills. I'm running it on an Edelbrock aluminum intake. Is your 500 a 4BBL or 2?