Anyone know of any fb 12a turbo manifolds. I've seen maybe one or two but wanted to see if there was any sneaking around that you might not get a Google result for, like mtheory. T4 btw

 

A factory 13B manifold probably fits.

I found that nonturbo 12As and 13Bs used the same exhaust manifold casting, they just moved the bolt holes 5mm off center one way for one engine and 5mm the other way for the other. The exhaust ports in the manifold are larger than the ones in the engine so there is no port mismatch on either engine. If you look at the ears on the castings and see the carbon witness marks on a used gasket, this becomes plain as day.

When I was restoring my '81 and could not find a 12A exhaust manifold, I used a 13B manifold with the mounting holes elongated to fit. Worked just fine. If you go back a loooong ways you will find that they used to do this in Australia to stick FC turbos on 12As. Given the fragility of the 12A without a lot of work, I wouldn't worry too much about making more power than a stock turbo can provide.