Like Dezert already said, piston protrusion is irrelevant Spoo. You need to set up your pistons correctly with the rod height, etc.. After 10k miles, my 408 didn't drink oil (well, not before I galled the cam bearings anyway).

390?? I think you are over-thinking all this. Yeah, I said it. Rex, you stop laughing now

 

For a 390ci you must be planning on using a 3.825” crank. Callies just happens to have one in their new C-Series line of cranks and should prove durable enough even being made out of 5140 steel and is pretty darn reasonably priced.

 

I'm planning on going with 6.300" rods, custom pistons to move the pin height up and a 3.825" crank on a 4.030" bore.

(4.030 x 4.030 x 3.825 x 8) x .7854 = 390.32 ci

That should keep the pistons from protruding to far outta the sleeve and rocking around, the rod length should reduce side loading, pistons pin height will be below the oil rings as well.

 

yup.
I was typing up my last response when you posted up with the crank I'm figuring on using. I figure I'd try something a bit different. I'm trying to build something under square rather than squared off. But still give it some stroke in the process without running into reliability issues.

 

Way below the rings, almost at the bottom of the piston. I knew I shouldn't have made up the 5/8" number.
6.125" rods.

 

This should help you visualize the "wobble"

http://www.youtube.com/watch?v=TPvrDIcx7Ec

 

 

lol watching that makes me wanna you matt

 

Go .060 over for 396!

 

reading this thread I was like hmm, a 396 might be badass lol