what housings do I use to change a 6-port 13 n/a to a 4-port 13 n/a. I will bridge port the motor once i find out what housings to use.

13BT end plates and rotor housings if you want....sounds like a fun project!

you can use 13b turbo II side housings and intermediate or 12a side housings and intermediate, but by using 12a u would have to change the motor mounts around.. or u can use 84-85 13b 4 port side housings and intermediate... i would advise u to use 4 port.. specially when running a bridge port.. perfect setup

How is the difference between the 12A side and intermediate housings, to the 13BT units? i.e. which would have more meat for porting?



'84-'85 13B is six-port only BTW, presuming you mean GSL-SE bits.



J

it depends if u r talking pre 85 13B or post 85 13B.



86 and up 6 ports, ud need turbo2 side housings, intermediate would be nice too, to get rid of the EGR hole. as far as rotor hosings, u can use 6 port ones, it just takes more work to port the exhaust.



for pre 85 13Bs, well actually 84 and 85 13Bs were the only 6 port ones, the 70s were 4 port. but for the 84, 85, u just need 12A side housings, i think, not 100% sure, that the intermedieate on 84 and 85 were the same for 12As and 13Bs.



and the difference between 85 and 86 is the location of the "O" rings. on 86 they are on the side housings as opposed to the rotor housings in 85.



hope that helps...

ok , I see this is going to be more difficult than I though. I have a 88 block so the 12a housings won't work without maching coolant seal grooves in them. Same thing with the pre-86 13b. So I guess turbo ll housings are the way to go without machining. Unless you guystell me other wise!!!