which is better for a 440 bore; 12.5:1 or 11:1.. thanks

 

I would go 11:1, that way you can run 93 octane. 12.5:1 requires race fuel I think. It's up to your wallet mostly!

 

Yup. Exactly what he said.

 

The big bores start losing head gaskets because of head studs after 11:1. I have an 11:1 416's and it has enough compression, though I have never checked it.

 

If you really want the 12.5:1 you probably SHOULD go with longer head studs. I always see them on ebay for $40.

 

i think im guna go with the 11:1. with the 440 kit from wiseco including the stage two cam and a port job how many more ponies am i lookin at? will i be able to run with my friends yfz? thanks

 

With the right porting and cam you can run with the 450's. It'll take more to beat one, though.

 

I would say mid 30's at least, and possibly more.

 

It probably can be done.
Just for reference, a well jetted, piped YFZ is putting out around 47 Rear Wheel H.P.
The YFZ is also lighter than the 400EX, so that is something else to take into consideration.[img]i/expressions/face-icon-small-wink.gif[/img]