They sell complete aluminum repro manual 16:1 boxes. $395 from PST. All new, bolt in.
Standard ratio length pitman are are pretty close to HiPo manifolds. Any longer pitman will need custom headpipe and possible milling of the manifold at the head to change the location of the header flange. The custom headpipe will need a quick turn and pinch flow.
Cost to do all that will be more than $395 if you are paying someone else. Even the cost of milling the manifold at an angle would be $60-$100 to start. Custom head pipe will be 2-3 hours to start from good exhaust shop. So there's $160+