I am going to be building a motor for my 85 gs I want to stay with the 12a but I want to buy housing that have already been ported. is there anywhere I can do this. I would rather not have to buy housings and then ship them off again to have them ported... I smoked the other housing. there is no crome left on the bottom of the housing. I am not sure what I should do can you help me out and guide me a little

 

I know racing beat does it.

 

Get the 12A turbo/12A six port rotor housings. They have 10º more exhaust port timing than US-spec rotor housings. No porting required unless you just need a little more duration or whatever. I think the cost difference is like $10, but it's been a while. Ask Atkins.