I've had way too much trouble in the past with the tin valley covers...oil getting "sucked-in" under the gasket! I'd much rather use a plate..and stand-alone composition gaskets..like the Hughes #3266's I just got. They're over-sized to fit ported factory-sized port windows! I trial-fitted one on my Eddy's last night..not much trimming to do at all! Looks like they're going to work well! I'll post a pic of the match shortly! If I can't find a plate with a closer-tolerence fit to the head...I'll just use the Indy plate again!