The flat design has been used successfully for quite a while. Pretty sure WOP had the first flat plenums...we sold a bunch over the years before the buyout. I have a set on my race motor...held on with international grey sealant...they have held fine at 118psi. I would take sealant over an o-ring any day.
Misunderstood by my stupid smart phone!
Thank you sir!
I like the idea of a cleanly installed/removable o-ring but if less service means using a wet sealant, so be it.
Its a tough decision with so many quality parts to.choose from. There are worse problems to have I suppose,lol.