That's the original Blue Streak. And a darn pretty one at that. So, no dovetail grooves, which is just as well.
The modifications do not increase the per pump power level. It will have the same power at five or six pumps as it does now. The limit on a "stock" Sheridan is eight pumps, where they will achieve about 620-650 fps. The Steroid mods raise the limit to 14 pumps, where they will achieve 770-790 fps, a pretty worthwhile increase. No need to use all of that, though, you can keep shooting it just like you do today. It's nice to have in reserve, though, for those across the yard shots on rats a squirrels.
I never pump my old '63 up very high at all. I just like the idea of more durable, quality valves and the pump arm. I do use the other two for rat shooting, and have actually killed a few possums with the Benjamin using the 25.4 grain JSB Exact. I'll use the full 14 pumps when doing that.
The key is how much air pressure the exhaust valve and striker can "clear" from the chamber. The stock setup cannot clear any more pressure than eight pumps provides, leaving residual air in the chamber. Tim's valves and strikers simply allow more pressure to be cleared.
Here is my '63:
