i installed a pair on my last 8 but those didn't come with the thick middle washer...

didn't know if it was to provide a little extra beef on the top to tighten down or to thin out the surface where the mount rests on the bottom.

 

When they first came out it was claimed that they maintained the original engine height, but later one of the racers here figured out they actually lowered the engine position. In some racing classes an engine mount change is allowed, but the engine can’t be lowered. The thick washer and longer bolt was added to place the engine in the OE position.

Some of us replaced the large washer with an even larger one; almost the bushing OD, because the large one being supplied tends to sink down into the bushing material. The super big washer spreads the load out more on the bushing.

Can you measure and post the thickness of the thick washer? I don’t recall anyone ever posting what it is.
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Thanks for the comprehensive reply.

The micrometer reads the washer thickness as 0.275".

 

thank you too.