GMC 228 intake/exhaust manifolds will not fit Chevrolet 235.
I don't think that elongating the holes on the 228 carb so it will fit the 235 intake is a great idea. George (Wrenchbender Ret,) said he has seen it done but he stopped short of recommending it. He said you will lose power.
So, I think you should live with the carb that came with the 235. If it's an automatic choke model you can get a manual choke conversion kit. Or, you can get another carb. If you want to get another carb, you might want to consider a Carter. There are knowledgeable members of this forum who will tell you that the Rochester is inferior to the Carter. There's plenty of discussion on this topic you can read - use the search feature.
