Let's talk about the Dorman 635-502 Engine Timing Cover. First off, when it fits, it fits WELL. Several users reported perfect OEM-like fitment, especially on Mercruiser V6 4.3L engines. The quality feels solid - definitely not some flimsy aftermarket part.

BUT (and this is a big but), installation can be a NIGHTMARE. Multiple reviewers had to perform what I call 'garage surgery' - trimming the lower lip, adding excessive RTV sealant, or even completely modifying the part just to make it work. One poor soul couldn't even get proper bolt alignment!

Here's my pro tip: If you're installing this on an in-place engine without dropping the oil pan, grab your Dremel tool because you'll likely need to modify that lower lip. And for heaven's sake - use gasket sealer! Even when it fits perfectly, that extra sealant makes all the difference against oil leaks.

The real kicker? This part seems to either fit like a glove or require complete modification with zero middle ground. My advice? Buy from somewhere with easy returns just in case you get a finicky one.