When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
For max hp and porting and assuming you are using pre-86 engine parts, go with the 4-port. You can use 12A end irons since the old school 13B 4-port end irons are getting extremely hard to find.
Not sure exactly what you're trying to accomplish? The only the 13B housings and irons from the SE will work with the 12A parts. Most people use the SE housings and the 12A irons to make a 4 port 13B. 12A=1146cc 13B=1308cc