Vintage gasoline class question.

[1gsxrclosertodivorce]

The rule book says....

12.I. VINTAGE: GASOLINE "VG" *
Motorcycle engines production date prior to 1956. Flathead, OHV,
and 2 stroke engines must retain the O.E.M. Heads, Cylinders, and
Crankcases originally installed at time of factory production.
Allowable overbore in this class is .050" (inch).
GASOLINE ONLY. See section 2.F.

My question...

Are there any limitations on modifications (obviously not a supercharger or turbocharger), both internal and external that can be made to "the O.E.M. Heads, Cylinders, and crankcases originally installed at time of factory production"?

Thanks in advance,

Andy

[Stainless1]

multiple answers to your question, depends on class...
Production... no external changes, all the internal you want
Modified, Altered and Special Construction Streamliner... all the internal and external changes you want...
You can run them blown in all but production.
Anyone have a different take?

[saltwheels262]

that sounds about right.

franey

[wobblywalrus]

Stainless is pretty accurate.  In addition, the displacement after the mods must be appropriate for the class.

[panic]

Not sure if that exact wording is new?
The rules as I remember them specified original heads and cases (but not barrels) for OHV, original cylinders and cases (but not heads) for side-valve, yes?

[1gsxrclosertodivorce]

That quote is from the 09 rule book

Cheers,

Andy