Me neither. Tried them I believe on my 90 W150 318, might have been my 78 w/360, both have oem steel covers I checked the bolt holes, nice and flat, torqued properly and it was leak city. Snugged some more and still leaked. Maybe for cast covers they’d be fine. I only use the Mr Gasket Ultra Seals now. Work great and so far have been reusable
I guess I can honestly say I haven't been brave enough to give them a try... At the point that I built an entire engine painted it and resealed everything with a whole gasket kit I'm not willing to risk getting oil dumped all over it....
