Welcome. Save yourself some aggravation here and just order a rebuilt unit from Rock Auto. Prices are fair and the quality is really pretty good. I have bought quite a few carbs from them. they also have a send in and rebuild option for carbs that they do not have a good supply of cores.
For a 74 250 its like $132.00 with a core return, $65 more if no core to return, and you get a guarantee.
