I have the same question.....how did the compression fail? Rings? Valves? If it doesn't smoke or use oil, I'd just do a valve job if money is tight. If it's a high miler/smoker, plugging in another good used 273 or 318 is the next cheapest route. A 318 or '68-9 273 will need a bushing for the crank to center your '65 torque converter. Everything else should bolt on if you use a '74 and older engine. Newer than that, you may have to modify smog provisions in heads and manifolds. You'd have to call around your area to get rebuilding costs from machine shops and parts suppiers. A lot will depend on how much of the work you'll be doing yourself.