I've been doing a ton of research for the best approach to get more power out of my 525sc engines. I know the blowers are small and produce heat so I'm not inclined to add boost. I can pull the engines and do heads and roller cam swap or leave the engines alone and put 250 blowers on. I'm limited by space so I don't think anything bigger will fit. My question is, what will produce more power? Are the 250s worth the money compared to what heads cam will give me but leaving the small blowers on? Thanks for any input.

Blower scoop. 420s. Roller cam and upgraded valvetrain.

How much taller are the 420s?

Here’s some good blower info.

Basic Blower Measurements - Wallace Racing

All of those b&m, Holley, weiand blowers are hard to get parts for and intakes are nearly extinct. Go with 6-71’s that you can parts for anywhere.

Just swap out to an 8-71 full kit. Use your existing cam setup. This swap netted almost 20mph on a twin setup.
Best Street Strip Blower Kits and Blower Repair 471, 671, 871

not touching anything but going to 8-71? What kind of boost after the swap?

You run the 525SC at 8# of boost without issue, but highly unlikely that you can even find a smaller top pulley. They are pretty much extinct. You need to change the blower lube frequently.
I was ran one for years(boat came with smaller pulley) and then did 731 roller cam and top end refresh. The extra boost and cam add about 50hp.
Use the advanced search and search my screen name and 525SC. Lots of threads with info from lots of people.