Hey Cheesemaker,
That is an interesting comparison, and I assume you are attempting to judge the “quality”.
Just to comment on judging the quality based upon visual and feel. The OEM product is designed for production at the factory, first time install. The aftermarket product is designed for post-factory installation. In terms of design criteria, the manufacturer, like Fel-Pro, may development their gaskets for the conditions most often found in the post-factory use and aftermarket headers.
Without a complete, technical, and scientific understanding of the specific materials being used, and how those materials respond to heat and pressure at the point of install and over time, the “feel and thickness” may or may not be a valid judge of overall quality or lasting performance.
Using a belt sander to clean up the exhaust manifold is OK, if you are certain that the mating surface is perfectly flat. I assume you used a feeler gauge and fine straight edge?
From my experience with new gaskets (OEM, Fel-Pro, and whosever comes with engbldr’s kit), the exhaust manifold or header nuts, once installed, need to be checked for proper torque very shortly after firing the engine – like within 1 hour of drive time. Then again after a couple days, then again in a couple weeks - assuming the vehicle is being driven.
Also, I believe the exhaust leaks I’ve experienced in my 22s have been caused by improper clamping against the head, the header mating surface not perfectly flat, and not necessarily the gasket used.
Based upon the comments from those who have used the Remflex exhaust gasket, I’m going to try one.
That's just my opinion - it may be worthless.
Gnarls.
