correct bb manifolds?

[tony digiorgio]

Hello everyone, I happened to run across someone with an extra set of big block manifolds that I may buy. One of the manifolds appears to be correct, however in large letters it reads GM2, this is not consistent with the other manifold that just has a GM on the outside. The gentleman tells me these were taken off of his fathers 67bb, however that casting number on the manifold with the GM2 is not readable. The date of the legible manifold checks out b 21 7 and has the correct casting number. Can anyone tell me if this is a matched set or is it a mismatched set? Tony

[Joe L.]

Re: correct bb manifolds?

Tony----

There is really no such thing as a "matched set". Manifolds often have different casting dates from side-to-side on a given engine, although these dates don't usually differ by large time spans.

The "GM2" designation is a mold number; it would only be an accident if both side manifolds had the same mold number for a given casting number. Correcting casting numbers for your car would be GM #3880827, left side, and GM #3880828, right side. Manifolds of these casting numbers were produced both with and without A.I.R. fittings. Unless your car was an original California car with K-19 option, you require the version not equipped with the drilled and tapped fittings.

[Joe L.]

Re: correct bb manifolds?

Tony----

There is really no such thing as a "matched set". Manifolds often have different casting dates from side-to-side on a given engine, although these dates don't usually differ by large time spans.

The "GM2" designation is a mold number; it would only be an accident if both side manifolds had the same mold number for a given casting number. Correcting casting numbers for your car would be GM #3880827, left side, and GM #3880828, right side. Manifolds of these casting numbers were produced both with and without A.I.R. fittings. Unless your car was an original California car with K-19 option, you require the version not equipped with the drilled and tapped fittings.