21-09-2017, 09:53 PM
Alan, I wouldn't use an extractor, they don't work particularly well on small holes. You will have to drill a hole in order to use it so you may as well drill tapping size for 1/4 BSF and retap it.
You could use the manifold as a drilling guide by getting some one to turn a steel tube, OD to fit the manifold stud hole, ID 1/4 BSF tapping size.bolt the manifold back on drill , not to deep, probably no more than 3/8" then tap.If you find it difficult to tap square to the face use the manifold again as a tapping guide
You could use the manifold as a drilling guide by getting some one to turn a steel tube, OD to fit the manifold stud hole, ID 1/4 BSF tapping size.bolt the manifold back on drill , not to deep, probably no more than 3/8" then tap.If you find it difficult to tap square to the face use the manifold again as a tapping guide