Yes, the build is a success.
 

Yes, the build was a success and the goal was achieved. Although the HP was a little bit lower than expected it is certainly enough for a street car at just above 510. The torque came in at around 520. These are dyno. proven results and and not fantasy numbers. I could achieve more HP by changing the carb from the 770cfm Street Avenger to an 750 or 800cfm double pumper or Demon, and more yet if I went to a Victor or even Victor Jr. intake. With those changes it should easily be in the 550+HP range, but I like the low end power of the Performer RPM Air Gap and am willing to sacrafice the higher RPM gains of the Victors for that, as that's where I usually use/want the power for the street.
I have gained about 225HP from what I had with the old 351 in the car and it has completely changed the personality of the Cobra from mild to wild.
I do miss some of the streetability of the old mild engine as this one does not do "slow" as well. But it's a trade off I am fine with and this engine is still quite at home in most situations and traffic. No problems with cooling at all but the cam makes the car a wee bit lumpy below 2000-2500 RPM and the sweet spot is up around 3000 to 4000 so gear selection is a slighly larger issue than with the old 285HP 351 in that way.
The 351 produced very smooth power at almnost any RPM but there was also a total lack of drama and aggressive potential as well. This 418 is an "animal" and requires a bit more thought to drive as pleasantly but the reward is the power potential it has for excitement when called on to produce it.
It's now your turn to build yours soon and we'll see if you can do even better with your build.
The biggest gain for me is in the satisfaction of doing this myself with no previous experience at it, and knowing every part in it "personally". Building this car and especially this engine is a dream I have had since age 16 when I saw my first 427 Cobra close up. Now I've finally (at age 63) done it. Far better late than never!
Nothing you simply "buy" can give that same sort feeling of accomplishment and pride in my opinion. (not that there's anything wrong in buying an engine/car, but it's just not the same as when you actually build them yourself)
None of this could have been done without the incredible advice and support from the people here on these forums and other Cobra owners and builders here at ClubCobra.com who were always more than generous in providing the answers I needed and expertise I lacked whenever I asked.
D.