I just found this old thread. Being in the process of building a 914 4AG swap and having worked with the 4AG engines a lot. A ll I can say to 500hp is oh sure for about 10 minutes. F1 spends millions of $ to get reliable 650hp out of a 1.6 with limited success.
(you can fool the fans but you can't fool the players)
I'm using a 16 valve carbed unit as a test mule to sort out cooling and related install challenges. Using a Kennedy adapter and fly wheel.
Then on to a 20 valve with flat slide carbs and some out board controllers for the ignition and VVT. These are all things I have done before so a relatively easy swap.
You can squeeze about 175 HP out of a NA 4AG (reliable/drivable) Formula Atlantic cars are now in the 240hp range(NA). So for a 914 175 is plenty considering it will weigh in a bit less than stock and rev to 8500.
Click to view attachmentSoooo tamp down the unrealistic HP figures and go Natural aspirated, use the 914 box and you'll have a car that actually exists. Or better yet just get an MR2 and skip the whole thing.
Oh there I go being harsh on the newb, but the whole thing smells trollish.