I owned a 1963, a straight tail, fast back, had no problems getting over Corona pass, just west of Boulder, CO, 9700'. Did it with passengers. Then about 10 years later, purchased a 1969, much prettier but with back window. Could not climb enough to get over Corona Pass. Now own a 1959 straight tail, fast back, and am able to get up to 12,500 to and from my cabin in Westcliffe. All has the O200 engine, and low engine time, and climb props.
Joel Kiester N7766E