Whats the biggest Porsche engine capacity

[pete917]

Whats the biggest NA engine capacity that porsche built for the 911 upto 1989?

The biggest I have heard about is the 3.9RSR engine. Is there bigger?

I am trying to think about a project engine and wanted to go as big and as powerful without a turbo...

Any ideas fellas?

[skinnerd]

Others can chime in or correct me....
but possibly as high as 4.0 or 4.2 liter.
Expensive, expensive P & C's though.

I have a friend who did a 3.8 Varioram engine.
Dynoed at about 330hp, 300 ft-lb of torque.
He said it was the fastest, scariest thing he's ever driven (car weighed about 2200lb)....literal rocket sled.
Can't imagine why you'd need more than that?
That's a $20k plus motor as well.