How big of a 4 barrel on a stock 1970 318?

Know what you're doing? Oh, you mean like when you used a stock intermediate shaft with an HV oil pump. Yeah that kinda know. I get it now.
340strokes is a subcontractor. He makes good money and has nice stuff and let's other people get greasy and dirty. I'd be highly shocked to find out that he's doing any more than talking about adjusting a carburetor and probably doesn't know a jet screw from a idle screw.
And to the original poster just so you know who to listen to watch how many people agree with me....