You could get around 500 if you play your cards right. Run a cam with a wide LSA and you can get a bigger cam to have better vacuum. Probably could use around 230 to 240 @ .050 with 112 to 114 LSA and still get decent vacuum. Run a cam with as much lift as you can, roller is preferable. Use higher ratio rockers if you can. I would look at 200 to 215 runners with some minor pocket cleanup, keeping the velocity up. Ported if you can afford it. If you don't have already there are some good high output HEI's available.