SBC Stumbling at speed help!

Here is the deal 1960 283 sbc with a edlebrock 1403 carb and a hei ignition. Starts up good, idle speed is good. Infact everything is great until about 40 mph then the engine falls on it's face, boggs down, pops when I give it gas, and usually dies. It's got a 700r4 trans, it does it both in drive and overdrive. If it stalls it'll fire right back up and if I blip the throttle a few times it'll smooth back out. Then its fine until I hit about 40 again and we start all over!
I've checked the plugs, they look good, not fouled, wires look pretty new, hei looks good, idle speed seems good. PVC hose is hooked up and the distributor advance hose is hooked up.
I don't have a clue what to check on the carb, the edelbrock site has alot of info on idle setup but not for this situation that I can tell.
Any help? anybody have a similar experience????

 

it could be timing or it could be fuel. if it was fuel you should be able to power through the sudden rush of fuel if you have good spark. you may just be running out of timing at higher Rpm.

 

I'de bet it's a fuel delivery issue. Either not getting enough fuel at carb (fuel pump/filter etc.) or the carb is really lean at the cruise settings. Heck, it could be the choke staying on as well. (which would be too rich) If I pull the choke on on my 1405 carb, it'll not want to run at highway speeds if warm. Play with it.

 

I would check fuel pressure. Hesitation and popping sounds lean. replace the module in the HEI.

 

Thanks for the replys. I got on the phone with another buddy, sometimes your too close to the forest ya know! The car has a fuel regulator, not sure why, because it's running the stock fuel pump. The regulator was at 2psi so I checked it to see if it was clogged then set it to 5 psi (open) and the stumble is gone. If you can't tell yet this is a new car for me and I'm still figuring it out. I'll probably just get rid of the regulator, I've never run one on a standard fuel pump sbc before.

 

I had similar problems with a 500 cfm Holley two barrel on my 350. I installed a pressure regulator as I had mounted the tank in the bed of the truck, and figured that gravity would boost it too much. Anyway it worked for about 40 miles and then kept leaning out big time. I cranked it up to the limit on the pressure and it still didn't want to run. So I threw the regulator away, and it ran fine after that for several years.

 

you dont need a regulator with a stock pump.. shit can it .
Dave