1976 Chevy stumbles/boggs under load

[1979ChevyMorgan]

Well im back with my 76 chevy with 79 454, i drained my tanks after having a bad gas issue and now she will run but stumbles around 1500 rpm when im not in gear. Ill slowley accelerate and when I get to 15 it will stumble and then shoot up to 1700 or so. Then when I put it into gear it boggs down and really has no power at all. I dont know if its just my plugs being fouled or if there is still a little bit of water left in the tank. My timing is at 12 and my plugs and wires were replaced about 3 or 4 months ago same with distributor (everything to do with the distributor). Thanks for your time.

[bake74]

     You need to refresh our memories.  Are you the one that rebuilt the carb. here recently ?
     Have you done a tune up recently with new plugs, wires, rotor and checked the distributor cap ?

[1979ChevyMorgan]

Its a brand new Edelbrock 750, could it be somethign with my accelerator pump? Plugs and wires were replaced few months ago. Just pulled all the plugs yesterday and they were carbonized so cleaned them off and put them back in. This truck likes to be difficult with me.

[Irish_Alley]

why so much carb?

[BADAZ chevy guy]

why so much carb?

My question as well. According to my math, that engine will draw 670 cfm @ 6,000 RPM. And that's ALL it will draw... EVER! Unless you plan on spending a lot of time above 6000 RPM, a 650 cfm carb would be plenty.
Here's the math.
6,000(max RPM) x 454 = 2,724,000
2,724,000 / 3,456 = 788.194
788.194 X .85 = 669.9649 (670cfm)

[Irish_Alley]

For a stock 454  and 350 volley says a 600 is good for both

[jaredts]

I agree on the carb. size, but that's probably not your only problem.  Has it ever ran well?  Have you checked all of your spark plug wires to make sure they are clipped securely onto the dist. and plugs?  No burns in any of them?  Have you checked to see if the accelerator pump is squirting (with engine not running)?  Checked timing?  Fuel filter?