My original 830 was essentially what they call a 950 today. 750 main body with an 850 base plate. It was a good carb. Be careful with the 1000cfm 4150 carbs they can be hard to tune and booster signal recovery can be an issue at the shift points. I have two annulars and one down leg 1050. They are awesome on a 499-511 but an 850 or even 750 was better on a stock stroke 440. Just my experience on a few different cars ymmv.