well the only 300hp KA motor ive ever seen was a SOHC found in the 89-90 cars, they were used in some north american endurance races or something. (circuit track stuff like sebring) they were actually used in the s14 chassis for some reason (s13 is lighter but i guess there are race restrictions and after all, the s14's were partial tube frame and fully gutted etc etc)..

anyways, they had ridiculously high compression, probably in upwards of 12.5 or 13:1 and i know that they were NOT streetable due to the camshafts that were in them. they also were fully balanced and built obviously, and the design was to make power in the upper RPMs. i believe they spun to 9,000 RPM...but dont quote me on that.

honestly, you wont make 300hp n/a. i dont think it will ever be done. most people with built KA motors that go high compression have a hard time hitting 200whp on the dyno.

now if you wanted to build an n/a KA motor, and then use nitrous for drag racing it would work alot easier, as long as you got it tuned right. otherwise, youre throwing money at something that just isnt easy, but i mean if you have lots of money it can be done.

if it could be done, i would have done it by now, because i prefer a really nice torquey all motor. i liked my n/a KA, but i knew that the easy way to power is through a turbocharger.

you should look at prices of a VQ35DE from the 350Z and fabrication/wiring costs. you could have 280-300rwhp all motor with a good amount of torque, for probably the same amount or a little more than you'll spend trying to make power on an n/a KA.

but if you go for it good luck, and dont mind the haters because im sure they'll chime in sooner or later with "you're gay for even asking".

ps - crower just came out with some cams, you might try those, they seem to be the wildest (stage 4 that is) for the DOHc motor right now.