How dey do dat?

[07Maxx]

OK, so the 3.5L V6 in my '07 Maxx apparently has a 3.90" bore dimension (99 mm). That's HUGE! How did they punch such large holes into such a small block?

The 3.9L apparently has the same bore diameter but a longer stroke, eh?

[bszopi]

Yes. I'd have to dig it up, but they did some stuff to the block to get the bores in there like that.

[geoffinbc]

The bore spacing is big 4.4" just like a SBC. In theory they could make it any bore size up to 4.125: with siamesed bores. But I think the limiting factor is the deck width and cylinder head size. Which may be why they moved the bore centers outward on the block. I also think we need a head available with spread out and larger valves for the big bore motors.

[07Maxx]

I hope to find a picture of the block for these "big bore" versions.

Wow, I'm amazed that they've got a 4.4" bore spacing in that block--the engine looks so tiny from the outside...

(keep in mind I grew up when big block V8s were coming into being!)