just a thought as I recall the 240 uses the same bellhousing as the 302, 351w and the 351c anyone of which would make a great drop in motor (and they all use the same motor mounts) But if your looking for bragging rights and such then a 429/460 gets you there (but personally if I was JUST looking for the bragging rights the 429 SOUNDS meaner just cause people think 429 CJ or SCJ where as the 460 is considered a linclon or truck engine even though has as good as performance but it's a preception deal) The other option is a 514 stroker too.

IF it was my truck the answer is a big block but I am kinda known for running big blocks LOL. second choice would be a cleveland (many people that aren't even ford fans know what a cleveland is and are scared of them) JMHO