What size carburator should I use on a 1985 stock 318? It has a stock roller cam and a new Edelbrock dual plane intake manifold. We have taken a lean burn two barrel system off the engine and want to place a four barrel carb in its place. Anyone have any recommendations? I would prefer to use a holley if possible. AND do I need to have a full 12 volts going to ECU in order for the Mopar electronic system to work?

something small like a cater 625 comp series would probably work.

I have a Holley 650 that I could use. So a Carter 625 would be smaller right? do you think the 650 is too big?

My 650 Holley only worked well if I made the secondaries vacuum. a DP is too much too quick for a 318 . With 430's,26" tire and a 3000 stall, I could not make a dp 650 leave without bogging.

I can't get the engine to start with the Holley at all. I was questioning the size of the carb just to get it to run. Wonder if there is too much gas input in the manifold to start with! Doesn't sound as if that is the problem. I am also discovering a 1.5 to 2.0 volt drop at the starter relay in start mode. I am going to increase the wire size to the relay and check the voltage in start mode again. I feel it is either the voltage drop or the size of the carb causing my problem. Any recommendations?

650 vac or mech should work. You'll need small squirters and the jetting should be conservative. Make sure your float levels are good. They will dump gas if they are not. Plug a plug and see how much gas you have on the plugs. Also check the spark at the coil and at the plug.

Super, I have brought the jets to 64, the smallest in the Holley kit. Reduced the idle adjustment to one and half turns out. Spark at plugs look weak, therefore the question about the voltage at the starter relay. I think the starter relay is not set up correctly. On my 71 Challenger the relay has the starter wire to the ballest resistor on the same terminal as the wiring from the battery. I need to go back and check the wiring and voltage in the whole front end of the other cars I have

I run a 600 eddy carb on a 88- 360 headed 318 roller cam engine with an LD4B intake

lunati voodoo roller cam 60710-comp 901-16 springs,stock roller lifters and valve gear

258/264
207/213
.485/.485

works great,set it and forget it till its dirty

never been one to tune on holley gas holes

the universal holley 600 works great for the swap to a 4-v on a a sb driver

I also by pass the BR and run a points dist with a pertronix points conversion kit with flame thrower coil..I give it a full 12V with the ecu unpluged and BR bypassed

never used the elect mopar stuff and ecu myself

Hey

In the past I havent been a big Edelbrock fan, but I put an Edelbrock Performer 600 on the stock (eddy LD4B intake & electronic ignition) 318 in my '67 Coronet and it ran absolutely flawlessly all last summer. It got better gas mileage than the stock 2-bbl did too.

Great information. I have been using the Mopar electronic gear for years and it has been very reliable. But, I can't start this engine. I am going to get a 600 cfm carb tonight and put it one tomorrow. I think the engine is just getting too much air/fuel.

I bought a new cam, purple shaft, before I was aware that this was a roller cam. Screwed, but can get another one. Like your recommendation on cam size.

I am at my wits end. I am going to buy a new carb. Not sure I want a edelbrock either, but will consider it depending on what is in stock. Have an edelbrock manifold, maybe an edelbrock carb too. Thanks

I converted my stock 318 2bbl to a holley 600 cfm universal. Vaccum secondaries, electric choke.

I got a 340 4 bbl Single air cleaner off of a
later model car, so it retains the heated air cleaner. I got the 4bbl throttle linkage off of
a 78 4bbl Diplomat (I think)...

The car starts and runs beautifully.
In fact, the vacuum is up almost 1" hg because
the air horn isnt warped on the new holley.

I used an old MP P4529116 aluminum intake.
Felpro gaskets and I closed off the heat riser
ports.

Like I said starts and runs with no problems.
The biggest boost that I get is at highway speeds
when I want to pass somebody...
I get a nice pick me up there...

Otherwise there isn't much difference vs.
the 2 bbl carter.

The idle speed is the same (700 rpm) with automatic (904)...

I run factory A/C.

Even after the car is started cold (and exits fast idle) with the AC on full blast
car idling in park with headlights on, blower motor on,,, car idles nice and smooth.
just like it did with the 2bbl...

The engine setup is stock though...
no change in heads/camshaft/.
its a 318 block bored .030 over...

Having done this upgrade recently,
I wished I did it 10 years ago....

Hope this helps...

600 holley is topping my 323" has the 340's cam .430 / .444" lift , And Edelbrock " streetmaster 318 " single plane 0-4800rpm intake. Using the 1.88/1.60 heads , 4 speed, and 3.23 gears its a nice package. In a 4 dr 70 valiant family econo box with 225/60 tires it went 14.89.

As fast as the first 4 gears of a stock 90's 5 speed 5.oL mustang.

Fast as a 77' 4 speed corvette with a 350 v8, performer intake , cam , and stock 3.36 gears.

Helps a lot. Great information and will keep in in mind as I continue to upgrade. I picked up an edelbrock 600 CFM carb last night and installed it. Looks good. But, won't start. Having to check my wiring, timing now. Still wonder if the voltage drop is why it won't start.

Thanks everyone for the advice. Now I have figure out if there is a voltage drop problem.

Well, guys, I was at wits end last week working on starting this engine. It is in an 1985 Dipomat. As far as I could tell, there was nothing done to this engine during its 70K orginal miles. I bought a new Eddy 600 at the local auto parts store and bolted it on. I have been through everything that I know about setting the engine up to be sure that it would run, not just start.

Well, to make a long story short, I finally blew my top and starting turning the distributor, CCW, until it started and ran like a top. The whole system is 90 degrees off from where it should be. I beleive that the lean burn system on the engine was set 90 off to accomodate something in their system. There is a debate running concerning this at the dippy site, but the truth is; the engine is running great with the 600 carb. In fact my neighbor who I bought the car from told me that the car sounded better and quieter than he ever knew it. Of course I replaced the plug wires, cap etc. The 600 is working great!!!!

you can run a flat tappet cam in a roller block with corret lifters and push rods

my roller block had a slider an I swaped up to a roller and stock roller lifters and push rods

pul the dist and turn it 180* and drop it back in

it either on or 180* out and can be wired to run that way

some times the vac can hits stuff so you would turn it 180* to gain more room to adjust it

There's no reason it would be 90 degress off because of the leanburn system. It was probably apart at some point before and someone didn't put things back together in the same spot.