HiProfile

Well here's the deal. I took my block and pistons to the shop to get bored, told them the motor's goals are literally 3-4x the stock output - high boost (for the street anyways) - and to size it accordingly. Once I got it back, it was exactly to the wiseco spec sheet (.0025), rather than the .0030 that people here usually suggest. The only saving grace is that they measured it with the black coating on, so from what I hear, thats an extra, although paltry, .0001-ish more. I'm thinking of opening it that extra 5 tenths with a hone, as I will be using extremely sensitive mitutoyo & starrett tools to measure with.

Should I go through with the extra bullshit?

My main concern is piston-wall contact, because I pinned the block (alum studs with devcon to seal it) and plan on doing upwards of 21 psi on this d16z6, with a built head later on. I also hope to put at least 10k miles on it, if not more, so I really have no margin for error. I'm calling Wiseco tomorrow about the specs, but I'd like to hear comments from people who've built at least a handful of 400hp d16's or 600whp b's.

HiProfile

Well I called Wiseco, they said for 300+ whp (20psi in their terms) they should be sized with .0030" clearance, which will give me ~.00335" when the coating wears off. Thats I guess the best part, knowing that the visible coating adds ~.00035" overall. That's one reason why Wiseco says to run their pistons at .0025", because once you break it in, the visual part of the coating is removed, giving you a good clearance.

I used a new 220 grit hone (not from autozone) to hone it out, and removed ~.0005" from each cyl. About a minute of low-rpm's on the drill removed that much. I also used Gunk Engine Brite for lube, as that's what I've used in the past for V8 builds.