I know that carb well, ive got those on my 79' international Scout II, and I've also cleaned one up for my 440 (little small but it'll run ok) Its a 625 cfm. They are O.K. carbs not overly impressed, word of advice...there is a metal flapper that is weighted just inside the primaries, THROW IT AWAY! What you will notice is if you give it a buncha gas....or floor it
It will spit one big PUH, then go like hell, its caused by that flapper taking time to swing open. Edelbrock makes a direct replacement accelerator pump for those.