Carter BBD questions

I have a stock '70 Duster that I just did a 2bbl conversion on. I put a Carter BBD on it, the one with the stamped steel cover over the metering rods. I bought it here as a rebuilt carb. I did take it apart and everything was new, checked the float level and adjusted it. It runs great, idles perfect, cruises perfect. The problem I'm having is you can feel in the throttle about halfway there is a spot with resistance, pass that spot it spits and sputters terribly. I have adjusted the metering rods, if you lower them it makes it worse. I have them adjusted all the way up, but they are now hitting the plate the covers them.

The strange thing is it feels more like a ignition problem, but it runs fine until you hit that spot in the throttle, and nothing was changed on the ignition. It will not do it while revving the engine in park. It ran fine with the 1bbl on it. I will have to say that I've always had Holley's and have never messed with Carter.

Any ideas?

Lowering the rods leans out the mixture, so what you are seeing is that you have a "flat spot", a lean spot. I suspect that your motor does't like your new carb.

power piston sticking not coming up to full fuel?

No, it's not like that. I'm actually thinking more of like @Murray. It seems like when the main jets are needed is when it stats acting up, and the fact that if I lower the metering rods it get worse.

I forgot to mention that I drilled the main jets out .005 more, but that didn't make any difference. It's runs great from off idle to half throttle. As I said I can feel resistance in the throttle halfway, if I don't go past there it's great. I think the resistance is where the metering rods are hitting the plates that covers them. Idk.

air bleeds clogged up

Didn't think of that, will check...

I hate it when there's no closure to a thread, let's get some. I haven't messed with the duster lately until this weekend, finally tired of the sputtering. In my original post I said that it felt like a ignition problem, it was. The mechanical advance, what I call the T-plate, was stuck. Problem solved!