The 98" is all bore. Put a 4 3/8" stroker crank in it and it would be a 107". This is all based on the 88" platform bike.

 

I'm running a 98" with Hillside Heads and Wood cams. Love it.....

 

Just a question that i"ve never heard answered in this forum. How thick are the cylinder walls before and after you bore an 88" to 98"? Seems to me that at some point, you will significantly weaken the cylinder walls. Although. I don't know where that point is.

 

The 98" is not all bore. All bore, or over square, refers to a configuration where the cylinder bore is equal to or greater than the stroke. An 88" reconfigured to a 4.125" bore x 4.0' stroke is an all bore 107". As you point out, an 88" reconfigured to a 3.932" bore x 4.375" stroke also displaces 107" but since the bore is less than the stroke, it is an under square 107".

While you can get to 107" with a 3.932" x 4.375 configuration, no one does for a variety of reasons. If one was splitting 88" cases to install a 4.375" crank, I doubt that they would install 88" cylinders bored to 3.932". They would most likely case bore to fit 4.125" aftermarket cylinders for a 117" configuration.

Not splitting hairs, just keeping terminology straight.

 

Copy on the terminology. We're getting off point here a bit. I was basically stating that you can get a 98" build on a 88" platform without splitting the cases. Someone here said you couldn't go larger than 95". That's the point i'm trying to make. When I said "all bore" I was meaning you can go 98" with cylinders and pistons, no lonlger stroke would be required. If you went with the 98" top end cyliners and put the stroker crank on it than it would be 107".