How big can you go in a stock block? How much horsepower can you pump out of a stock block? You can bye a bbc short block for about 4500 . But it comes with a dart block or a world block. i have a vega wagon 2440lbs with me in it and a sbc. it makes about 450 to 475 hp. it runs 6.70s in an eight mile. but we are still tuning it. I want to run low 6 or high 5 with out turning it to hard. So how much hp do i need?