Rat head/Ace piston

[MTrat]

I recently ran into a 100 with a Rat head over an Ace piston with two head gaskets to gain top end clearance. I assume the compression would be quite high and the Rat squish profile would be beneficial. This was on a bike owned by a prominent racer. Does anyone have any observations, theory or experience with this combination?

[taber hodaka]

I was shaving ace heads before rats came out. I don't know why they used 2 head gaskets, am I missing something? ------- clarence

[MTrat]

Because of the domed top of the Ace piston, it will hit the Rat head I believe. Clearance issue.

[dirty_rat]

I think the two gaskets are more to lower the compression to an acceptable level. I don't know if the piston would hit the head, but I don't think it would (maybe on larger overbores).
A quick way to check is to take some soft solder wire and lay it across the top of the piston so it reaches from edge to edge. Put the head on and slowly crank the engine through. Take the head off and measure the solder too see what kind of space you have at tdc. This also gives you an idea of squash band.

[olddogs]

Play Dough also works. I use it on top of air cleaners when checking the hood clearance on custom cars.