With the stock heads you will be making about a bit more than stock power. It is the heads that makes the power. The cam tells you where you will make the power in the RPM band. With a bigger cam you can make more peak horsepower but it will be so high in the RPM range that you will not be able to use it on the street.
The only thing you have done to raise the horsepower over a stone stock motor is to make it marginally bigger. The greatest contribution to power was made by your raising the compression from the stock 7.8:1 compression ratio to 9.1:1. Bigger valves in your stock heads would also increase your power levels.
You have to keep in mind that it isn't horsepower that you want unless you are planning to take your car up on the high bank oval track. To accelerate your car you want to make gobs of torque. This is why the 406 SBC is so popular. It makes more horsepower than your BBC 410 (40 over 402), but the same torque because it has the better head found on the SBC, and does so for less money.
Torque is made by cubic inches. If you choose to make those cubes by relying upon a longer stroke you will make more torque than if you where to increase the bore spacing to maximize the bore to make the same cubes.
An example of this is the 496 which was the last production big block made to compete with light diesels in pick-up trucks. The 496 was a 454 engine with a quarter inch longer stroke crankshaft (it also used bigger, to fit on top of a Gen V big block, LS-1 heads with dedicated EFI). Chevy also offered a 502 which is about the same displacement, but makes it's power by boring out the motor to a 4.5 inch bore. The 496 pulls like a diesel. It makes lots of torque, but slow reving with all of it's power made below 4,200 RPM. The 502 made more horsepower, but less torque, and had to rev to 5,400 RPM to make that power.
This is why the 496 is so popular (it is the 383 of big blocks). The best big block that makes the most power for your money is the 540. It has the big bore and long stroke that can be assembled from off the shelf parts. Go bigger and the price doubles quickly, but bigger is better with a big block motor.