383 Big Block Carb./Intake/ Cam issue

-
Fishinboy44

Fishinboy44

Member
Joined
Nov 30, 2010
Messages
16
Reaction score
0
Location
Palm Beach Gardens, Fl
I am currently running a 383 Big Block with a toker 383 Edelbrock Intake with a 600CFM holley on it. The motor has some sort of cam in it and I still feel a little hesitation at lower RPM's and not running like I want. Otherwise has all new Plugs, wires, distributor, Petronix ignition, exc. Please let me know if I should change something or look into running something else. Thanks
 
Fishinboy44 said:
I am currently running a 383 Big Block with a toker 383 Edelbrock Intake with a 600CFM holley on it. The motor has some sort of cam in it and I still feel a little hesitation at lower RPM's and not running like I want. Otherwise has all new Plugs, wires, distributor, Petronix ignition, exc. Please let me know if I should change something or look into running something else. Thanks
Click to expand...

First off you've got a single plane intake that can be dogs on the bottom end unless you fool it with a 1" wide 4 hole spacer and a big assed double pumper carb like a 750 (been there and done that). You didn't mention if you've got a high stall converter or your rear gears. Single planes want high stalls. First thing I'd do and have done is dump the Torker for a RPM Performer, dual plane, and get a bigger carb regardless. A 750 for sure, then that puppy should haul *** or at least you'll be going in the right direction.
 
Demon I agree with most of what you say, but a "big assed" carb is NOT a cure for low end hesitation, bog, etc
 
67Dart273 said:
Demon I agree with most of what you say, but a "big assed" carb is NOT a cure for low end hesitation, bog, etc
Click to expand...

OK bigger carb then cuss a 600 ain't big enough for a 383 even in stock trim. Especially when running a single plane which are famous for way lean off idle bogs, enough so that replacing a vacuum secondary with a double pumper can cure the problem. Regardless a good dual plane will probably cure the bottom end but still going to need more carb for the top.

Still need cam specs, converter stall and rear gears to get her singing.
 
I bought the car and I have no idea what size cam that is in it. All I know is that its there. And its got a 8 and 3/4 rear end and I dont know what gears are in that. Maybe factory? I dont know. But the motor seems to run better at high rpm's. And there is no stall on the trans.
 
I too would like to see a bigger carb. I put a stock, (60K mile) 1965 383 in a Valiant. These were about the lowest hp 383's made. I added a stock Holley pattern iron intake, and small dual exhausts off the factory log manifolds. That engine ran excellently with a 750 double pumper. Whack it at 30 mph, and it would light up both rear tires for a good bit. If that low hp engine liked a 750 cfm. that much, one with ANY modifications should need at least that big of a carb is my opinion. For a street car, I would get a Performer RPM intake also. Great intakes.
 
I agree that overall the carb is not big enough. That is a separate issue however from your hesitation. A properly set up too small carb will not hesitate. In fact, that will be the absolute last thing it will do. I would look at the accellerator pump lever. With the engine off, see how much clearance there is between the accelerator pump lever screw and the pump arm fromunder the diaphragm. The spec is .010" I bet it's much greater, or the accellerator pump is possibly bad. Even with the single plane intake, you should be able to tune that 383 to set your eyeballs back in your head from a dead stop with that 600. I wouldn't worry about a bigger carb just yet.
 
I would try to get it runnin with what's there first. That way, you will be sure that everything else is in proper order. Check the pump adjustment. It's very common for this to be way off. Also check the tune. Timing, plugs, float level, air screw adjustment. All of it. DIAGNOSE it first before throwin parts at it or you may never fix it. It will run GREAT with the 600 IF it's properly tuned and the engine is in good shape. The only place the carburetor will fall short is at higher RPM where it will be too lean for the engine. A 750 double pumper will only worsen things because you have an automatic. DP carburetors should be used only with manual transmissions or with automatics with properly chosen converters and gears. You can either take good advice that is free and will also cost you nothing to actually DO or keep asking questions and getting more different answers and runnin in circles. It's up to you.
 
Look inside the carb and move the throttle from closed to 1/4 a few times and watch for a nice squirt from the accelerator nozzles. If not check for 0 clearance on accelerator pump linkage. It is adjusted by screw on linkage. If the clearance is ok you might want to speed up the accelator pump by moving the little nylon cam on throttle linkage to the closer holes.
-1
We also need to know the idle speed. A larger cam needs a higher idle. 800-900 rpm with cam and open plenum. To low of an idle could also make it miss
 
You must log in or register to reply here.
-

Back
Top