1800 NB 5 speed stronger than 89 NA 1600?
 

As per the title, the wrecker down here says the NB 1800 5 speed is a stronger unit than the 1600 NA 5 speed. I think from an 94-96 is the one he has in mind.

Can anyone confirm or deny this for me....?

My NA 1600 one is developing a whine and as i intend to start increasing boost soon figure I may as well replace it while I am doing the complete NB 1800 rear end swap....

I think the synchros are better in the 94+ years. otherwise everything else is the same

All of the 5-speeds are weak. The only year-to-year change that I'm aware of is a stronger spring action in the reverse gear to help prevent the "stuck in reverse" phenomenon that mazda identified early in the NA production years. If you want something stronger than your 5-speed, your only bolt-in option is to get a 6-speed.

As far as strength is concerned... tell your wrecker he's gone full retard. He's confusing "transmission" with "differential". 89-93 differentials are slightly weaker than an unborn fetus. (I know, it's redundant to describe a fetus as being "unborn", but I stopped caring the moment I opened up these parenthesis.)

Okay on that info (thank you) I have asked the wrecker for his 6 speed.

He wondered if the 6 speed bolts up to the NA 1600, can anyone here advise?

yes, most definitely.

look for write-up for 6-speed swap