How important is primary impedence?

[arri93]

So I was looking at Rocker 30 mods just out of curiosity. I also have a bassman build that I'm doing with my Dad (retired electrical engineer).

I've seen a couple of people have replaced the ot with a 50w JCM800 output transformer claiming that they're more or less a drop in reaplcement.
I've looked at a couple of of 50w output transformers intended for for the JCM amps and found that the specs tend to vary slightly
For example one was 3.6 and the other was 3.2k.
It looks pretty straight forward and I know which wire goes where but I'm wondering if the difference impedance is cause for concern? If anyone more professional than me would care to chime in I'd be grateful

My plan is to replace the transformer and hopefully reuse the original 30w in my bassman build

[Racing]

No.
That slight a difference amounts to about zero.