is it possible to bolt four port side plates to 6port rotorhousings??i am planning on doing this and to keep my centre plate though jus use some four port side plates, and the last question is do any four port side plates fit onto the 6port rotor housings or do i have to buy the turbo side plates?? cheers

 

The rotor housings aren't any different. All four port side plates are from a Turbo motor (unless the FB ever used a 4 port motor). I know a guy that races FBs, and he is currently building a motor with 13b rotor housings and turbo endplates with a 12a center plate. Basically he is making a 4port motor that has 4 similarly sized ports.

 

so the sideplates from the older 13b engines from the 70's and early 80's (the side plates are four port)they will still fit????
..i am building up a motor that is consisting of: four port side plates, 6 port rotorhousings, series four excentric shaft and stationary gears etc, and 6 port intermediate housings. hopefully it will be bridgeported and all ran by a microtech. how much power do you think i will expect? i am hopefully going a fairly large bridge port and a pretty free flowing exhust, but still with a little restriction as i am going to try drive it on the street.

 

Someone else is going to have to step in here, as I don't have any experience with the older motors.

 

No. After '85 Mazda switched the water jacket o-ring location from the rotor housings to the irons. Therefore all our rotor housings are flat, while our irons have grooves for the o-ring. If you try to use a pre '86 iron, it will not have a groove to fit the o-ring.

You will want to use TII irons then. I would expect above 250HP. How much depends on a number of things (how good your tune is, what intake manifold, etc.).