I will kind of side with You on this, but one thing to remember is that exhaust tubing incl. header thin-wall is sized by OD, not ID. So the ID of 1&5/8" header tubes is damn
near 1&1/2" anyway if You want to go by port CA. The other thing to consider is that if You should decide to amp-up the program, a good set of 1&5/8" headers can put
a car like Yours in the low 12's, maybe high 11's,...You know the saying,..do it right once and........................................................
