What's your opinion on those roller cam 318s, with 302 heads, as opposed to the earlier 318s? I've got one I'd like to do the same high revving build you're doing. I think they all need help breathing, to start.
I know you asked 318WR, but my personal 2 cents is spend some money on good heads to couple it with a solid roller and you’ll be way way ahead of the game.
If stock heads are the sticking point and all you have are 328 heads, your behind the 8 ball and I’d start looking at some restricted racing classes & how they do it. A fella that knows a little something about it would be @Hysteric and a few other members who’s names are escaping me right now.