Edelbrock springs 1406 and 1405

I have to disagree with RRR about the method of choosing the correct step up springs. You need to swivel the piston tops so you can see the pistons. Use the strongest springs that will just prevent the pistons from moving [ lifting up ], engine idling, in gear. Once these are known, you can try lighter springs but you might get a bog because it is too slow to enrichen the mixture. Prolly only do this for economy, but I doubt that is a worry with two carbs...