Is it possible to make a 3.7l into a 4.0l?
 

I know with the aluminum block and steel sleeves it might be a pipe dream. With superchargers and turbos being a debacle in itself. Everyone would enjoy more power from these I-5 motors. Has anyone thought of increasing the displacement? I did it with an old Porsche I had a while ago with great success.

Maybe I should clarify my thread. Can a 3.5 or 3.7 I-5 be increased in displacement at all? Back in the 90s with 4.0l Jeeps a company made 4.7l stroker motors with them. I mean wouldn't a 4.4 stroker motor be so sweet! Mustangs might have to watch out at the light. lol Ok I am dreaming now...

L52 (3.5L) has a bore of 93MM (3.7") and a stroke of 102MM (4")
LLR (3.7L) has a bore of 95.5MM (3.76) with the same 4" stroke.

If you could open the bore 2.5MM, then you would have to deal with the rest of the process. So, if $$ were no object, it might be possible. In reality, your dreaming. ;)

Much easier and cost effective to boost performance with bolt ons, like an intake, PCM tune, CAT back exhaust, Efan conversion, and PP Throttle Body.

(wasatch, this is not directed at you.) It always amuses me when people say, "the I5 is so under-powered" because it clearly shows their lack of understanding as to what the platform is designed for. Even when powered by the LH8 5.3L, it is no bullet. GM did not mistakenly think a 5000# (stock) brick shaped FT 4X4 was going to be speedy and nimble. Nope, it is all about torque, I5s make a bunch at 2800-3000 RPM. In low lock, even without the adventure low ratio T Case, they have impressive off road ability.

In the 70s I had new 4X4 pickups powered by the 350 V8 that had almost 60 HP less than the 3.5L, and even worse in the torque! Granted, you could build those 350s to make loads power, but you have several cost effective bolt ons for the I5s that pump up output too, and boost that low end torque.

I agree…boring the engine wouldn't be cost effective. However, I wouldn't mind some extra power out of the I5 if I could do it at a decent price. So…all in all, it sounds like an intake and exhaust would be my first recommendation for anyone seeking more horses.

For sure! Thanks guys. I do agree this motor is like a tractor. With Adventure package, wheeling is effortless! I already have; K&N filter charger, Magnaflow exhaust, Dual Flexalite fans. I do want to try the header route as well as a ported throttle body and computer motor/trans upgrade. The latter would help me the most at this point, as I hate the motor always dropping into "eco" mode when I want to jam! My biggest issue is passing some POS subaru at 8,000 ft elevation. I would like to do it with more authority! If you know me I do not leave very many things stock. Always looking to improve. lol Thanks for the input...

Of course if you are looking for more horses out of your H3... It's called Alpha... 5.3
Tons of things you can do with the 5.3 V8.