Sorry 273, I see a lot of mumbo jumbo.
Bottom line, an extra 45 cubes due to bore size will make for a more powerful engine in HP and TQ across the board when otherwise equally equipped. What ever you do to the 273, I get to do to the 318. The 318 wins.
The chances? I’d call it even. And that chance I’d call piss poor. That is a 52 year old engine. I stated that the low compression of the 318 can be fixed by a low dollar head killing which is worth the cost of indeed you “NEED” that extra compression.
You can turn a 318 into a 340 easy?
Oh please due tell! I have yet myself find a 318 able to accept a over boring of .130. Is it possible? I just haven’t seen it.
Now about head flow. I agree. How that enters in the cubic inch engine vs. engine discussion when basically, from where I stand, they use the same head. The particulars of the exact head castings used on the engines throughout there run years and the flow rates of these heads I don’t have known in my head or even bother to keep on paper/lap top/ stone carvings.. LOL!
As I said, “Basically there the same head.”
Do you have a reliable chart that YOU personally flowed? A trusted friend? Some wacko internet source?