E49 spec 265 had 320+ hp, and easily get more with minor alterations.
265's had 1.96" intake valves, and 1.60" exhaust valves.
E49 spec cam had 308* duration for In and Ex, with 88* overlap.
The heads were Chrome alloy-cast iron.
Bore x stroke......3.91" x 3.68".....265.
