Since the upper manifolds on these things are impossable to fully port does anybody know what type of acid I should use on aluminum?.
You should use something stronger than muriatic acid, because acid won't actually etch the silicas that can be found in the aluminum manifold. IM acid porting experiments.
How does acid porting add air flow to cylinder heads and intake manifolds? Acid porting is the enlargement of the entire intake port using chemical treatments.