Out with the 340 & in with the 410 stroker!

So the motor came back apart after doing a leak down test and finding 22-24% leak through the int/exhaust valves.....Already posted this, I know...
It turned out the ferrea valves were not round out of the package, live and learn, they all get ground from here out.

So while the heads are off I've been cc'ing them and found the following...

Intake ports measure
Stock J-155cc
My modified J-184cc

chambers are 62-62.5cc , keep in mind these particular heads started out @69/66cc's- they had seats installed on the intake side and how ever much milling ? who knows..
I have removed .040 from 1 head and .020 from the other already, now another .0096 & .0144
I will mill them down to 60cc and call it good.
This should yield around 10.1 on the nose.

I have yet to measure the modified exhaust ports, but will post'em later.


I am gonna get some clay and cc the plenum of this old weiand single plane#7510 too