383 STROKER PROBLEM

I RECENTLY PUT TOGETHER THE 350 TO 383 UPGRADE WROTE IN THE CHEVY HIGH PERFORMANCE MAGAZINE LAST YEAR. DETAILS - 4 BOLT MAINS,POWERHOUSE STROKER KIT WITH RING UPGRADE, .030 OVERBORE, BALANCED, 500/510 CRANE HYDRULIC ROLLER CAM, PATRIOT HIGH FLOW ALUMINUM HEADS WITH SPRING UPGRADE, SCORPION 1.5 ROLLER ROCKERS, EDELBROCK RPM AIR GAP INTAKE, EDELBROCK 650 AVS CARB., EDELBROCK MECHANICAL FUEL PUMP, MSD ELECTRONIC DISTRIBUTOR, 2 1/2" FLOWMASTER EXHAUSTS.
PROBLEM - WHEN I EXCELERATE GRADUALLY, THE CAR PICKS UP FINE AND HAS GOOD POWER.  BUT AT ANY SPEED WHEN I GET INTO THE THROTTLE HARD THERE IS A BIG HESITATION FOR ENGINE PICKUP. THE CAR WILL ALMOST DIE, THEN GOES REAL STRONG. I'VE TAKEN THE CAR TO A COUPLE OF GOOD MECHANICS.  ONE THINKS THAT THE CARB IS DUMPING MORE AIR THEN GAS WHEN THE SECONDARY CUTS IN, THEN THE FUEL CATCHES UP.  BUT THAT'S JUST A GUESS.  ANY IDEAS ON CORRECTING THE PROBLEM. OTHER THEN THIS BAD HESITATION THE CAR RUNS GREAT.  

check at the timing, or play with the distributor  

While it could be a timing issue, it sounds more like the carb isn't tuned correctly for WOT on your motor. Either the secondaries aren't kicking in right or it just doesn't have enough fuel at WOT.  

Check your fuel pressure at WOT it sounds like it's starving, or maybe flooding.  If you have good fuel pressure it could be the accelerator pump is not providing enough fuel or your bowls are running dry.  It may be also be a timing issue, any pinging (too much) or since it's flat maybe too little.

Good luck  

what kind of distributor are you running and what kind of carburator are you using with it? it does sound like a fuel and air issue, check the plugs and find out what they look like. if they are firing clean, and it's not running lean then it's not your distributor,  atleast you'll know for sure if the carburator is the culprit.  

Ya it sounds like it's either too lean or rich.  

problem will go away when you dump that Edelbrock carb.  Try a Holley 770 SA, vacuum secondary if the car has auto trans.  Or, you can spend many hours and dollars trying to tune the thing to work right.  Is that engine in a heavy car like a Chevelle with auto trans and 2.72 or 3.08 rear gear?  

oops, forgot to mention, that engine will like the initial timing set to 15 or 16°, with a short curve to limit total advance to 34 or 36 all in by about 3000RPM.  

My first thought is it sounds like a lean condition when your secondaries open up. Maybe they're opening to fast, so the fuel can't keep up with the initial air "gulp"? I had what sounds like the exact same problem with a holley. I've never had an edel.(carter) carb, but on my holley I unhooked the secondaries and the WOT hesitation went away, so I knew it was the carb. Just my 2cents.  

I dont really see the carb you have now being big enough for your setup  

tranny kickdown cable ... i dont know but it was worth a shot lol  

I think it's called a booster.. But it adds a metered shot of fuel by a small accelerator pump controlled by the carb linkage.. It adds a healthy  shot of fuel, mechanically while there is a momentary loss of vacuum to pull enough fuel...  That devise is what I think is hurting.. EZ fix though.  

Not enough feul pressure? What kind of vac advance are you running? Is it adjustable or not? Just like others have siad it could be timing too  

Is it a mechanical secondary carb?
If it is opening all four barrels at once  will cause a temporary fuel starvation that the accelerator pump cannot handle. If the carb has vacuum secondaries the accelerator pump may not be working properly or be too small for your motor.
The other problem I have had on a race motor is the carb or carbs being too big for the motor. This does not seem to be the case with yours. The signal at the booster, ("signal" means the air passing the booster creats a vacuum which pulls fuel from the booster), would drop off when RPMs dropped off, such as when the motor shifted to the next gear. The motor would starve for a second and then take off. I don't think the latter is your problem.
The accelerator pump is most likely your trouble.
If you want all four barrels to open up at once you need a double pumper. That is a carb that has 2 accelerator pumps, one for each pair of barrels.  

a 750 double pumper would be better if you have the gears for it so you wont bog even more. timing and fule is wher you need to look.did you tune the carb or is it right out of the box?