like the title says. i swapped clusters & a few days later, my truck loses power as im driving. either battery failed or alternator. both clusters are from ‘92 so they should be plug n play correct ? very stressful. i will post pics of both clusters (F2TF is the new one with tach) , (F2UF is the original one it had without tach)

 

We are going on assumptions that may not in the least be related.
One thing you can do is put everything back as it was and see if it had any effect.
How do we know the power loss is battery or alt related?
Are we talking engine power or vehicle electrical power?