I was looking around on a website some of you may be familiar with, especially if you live in WA, atkinsrotary.com. Well on their list of services there was street porting and bridge porting. I am just wondering, what is the difference, is one better than the other and if one is limited to a certain kind of application? One more question, nothing to do with the thread title but is 3mm apex seals better than 2mm? I would assume bigger means better compression but I really don't know? Thanks for your help

 

Even in the new user forum, it is a great idea to search first. For example, I searched this forum for "bridgeport" can came up with the following that will answer your question:

https://www.rx7club.com/forum/showthread.php?t=901479 (from only a few days ago)
https://www.rx7club.com/forum/showthread.php?t=890902
https://www.rx7club.com/forum/showthread.php?t=798008
https://www.rx7club.com/forum/showthread.php?t=852231

To answer your second question, 3MM seals are generally used when your rotors are too worn to accept 2MM seals. Mazda moved away from 3MM seals a long time ago as 2MM seals offer superior sealing. 3MM seals are only marginally stronger then 2MM seals.