A few minutes with a spring tester and you should be able to determine if the springs are suitable.

For that application(and what you’re doing with the engine), if you can get close to 2” IH, I’d probably go with something like a PAC-1225.

I haven’t used “tons” of Manley springs…….but more than a few sets.
Nothing stands out in my memory with any of them being way out of spec…….but anything is possible.