440 invader bored out

[Rhettly464]

Hey there just wondering if anyone’s bored out a 440 invader or shaved the head down for more compression looking to get a little more gains outta my 440 wondering if it would make a difference.  Thanks

[Interceptor398]

Shaving the heads is not uncommon but boring the cylinder is.  They need to be sleeved first as they are chrome bores.

[gixxer6]

I was looking at doing a big bore Invader, but there isn't much room between the bore and the cylinder studs.  It isn't possible to go large enough to make a substantial difference. 

I am running kit pipes with trail ported cylinders, and shaved heads with custom shaped domes.  It makes a noticeable difference.   Depending on what you want to do with the sled, I recommend upgrading your clutches and track first.  More power doesn't help if you can't efficiently transfer it to the snow. 

[Rhettly464]

Huh interesting thanks gixxer6.  So as far as the heads what did ya take off? 10 thousandths?

[gixxer6]

Interceptor398 did the work on the heads.  They were cut to have around .070" squish.  They were reshaped so that the squish band matches the dome of the piston to create a uniform squish across the entire band.  They were cut to a measured 13.52:1 compression ratio.  All designed to run on premium pump fuel (92 octane in my area). 

If you don't want to get that fancy, you can have them machined to Aaen spec which makes for a nice improvement as well. 

[sprocket]

You can bore them then have them done here for plating https://www.usnicom.com/
Then for your rings you can run any. If you stay with the chrome bore you can not run chromoly rings and most piston kits (Wiseco) unless asked you get molly rings