If ever, for any reason, I had a B18/B20 out of the car and the flywheel off, I would simply not even consider not upgrading to the later design neoprene seal... Not only is it simply a better design, but since you're already there and with the engine out, it'll be a snap to get properly centered.

Imagine the hassle of doing the upgrade later, pull transmission, bell housing, clutch, flywheel... and even then you're working awkwardly under the car with bad light trying to get that thing centered just right...

Not worth it, man... an engine rebuild is a significant job. Don't skimp on the rear seal.


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-Matt I ♥ my ♂