| :In my previous post, I mentioned that I spoke with an Engineer at Jim Wolf Technologies (JWT) however, it's not advisable to post someone's name on the internet without their permission. So how about asking his permission??? The only JWT engineer I consider an authority on anything concerning the VG30DETT is Mike Smith, and he has never cautioned me against removing the spark plug boss. He removes it on most of his builds, FWIW. No offense, but you're a relative n00b on this site, so it would only benefit your credibility to reveal your references. Otherwise, it is all too easy to conclude that you're talking out of your ass like so many others before you. Don't get me wrong, I like technical posts like this, but you really need to back yourself up here with more data and references, particularly when you're posting info that is contrary to common belief. How about some more test data? Pictures of your test setup? Throw us a bone here... If you really want to drive your point home, flow data for stock valves vs oversize valves would help your argument. I do agree, however, that the commonly used 1mm oversized valves can hurt flow in a stock chamber. However, most people are able to sufficiently deshroud the chamber to see flow gains. Here is a set of heads that I did a mild port job on years ago, and saw decent flow improvements using .5mm oversize Supertech valves: [ http://www.twinturbo.net/net/viewmsg.aspx?forum=general&msg_id=1710125 ] Intakes were 260 cfm at .4" lift, and exhaust was 236 cfm. This was essentially a pocket port with chamber work to remove shrouding around the intakes. The port runners were smoothed, but the geometry was not significantly altered. The spark plug boss was smoothed out, but not removed. The client was concerned about the compression drop from removing the boss (which is of little consequence, IMHO) I don't have his dyno handy, but he made ~537rwhp at 18 psi on 93 octane, untuned. This was with sport 700's with the .64 housings, and all of the "breather mods" that are only now becoming popular 5 years later
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