I'm loving this because I've been debating on stroking my LS2 to solve my reluctor wheel issue, and the fact that I could make more power makes it more appealing. I can keep my top end as is.
Short vs long stroke is a very interesting comparison. 4" stroke vs 3.622" is basically like spinning 10% higher RPM all the time. Expect to pull the peak power down by 400-500 rpm or more, and fall off sooner due to airflow restriction and port tuning. Without a big cam it can be hard to make them rev happy. A 4" bore also makes it tough to get good airflow due to valve shrouding unless you stick with cathedral port heads, but then you pretty much need to step up to a 235-245cc intake port minimum to have enough airflow for the displacement. For the cam to behave similarly as what you have in the car now you can expect to add about 4-6* duration to the intake, and retard the cam timing a bit. If you keep the same cam it will behave like a milder cam for peak power location and driving around.
It depends what you're looking for. If you want an engine that will beg you to wring it out to 7200 rpm every shift a 402 possibly isn't your best route. My second little horsepower bump comes in at 6250 rpm which I'm very happy with. There's a thread on ls1tech that documents dozens of 402-408 builds and you'll see most are HP peaking at 5500-6000 and make less horsepower than your LS2 does. We've learned a thing or two since 2007, but this is a great reference for you to compare against your LS2.
https://ls1tech.com/forums/dynamometer-results-comparisons/816128-408-results-part-ii.htmlThat said, HPR is dominating the road race world by building induction limited 468 motors that make "crap" peak power compared to their potential, but make so much damn midrange power that they pull on literally everything else on the track. These are 900 horsepower capable engines that are induction limited to ~6000 rpm - but live forever on track, use big maintenance free hydraulic roller cams, and out accelerate everything. It isn't a traditional sports car power delivery, but if you're motoring past exotics tractoring around at 5500 rpm do you really care?
A 427 or 440 can definitely be the high reving screamer engine for you though if you want to make big power - so maybe think about sleeving your block. The 4.125" bore is a game changer, and even with a relatively small cam you can make them rev out to 7200 and make huge power. The ls2 block is RED's preferred block for doing darton sleeves - best strength in the block and performance is the best with the bay to bay breathing. Exidous is building a darton sleeved motor right now. My build is starting with an LS7 block because I found a SBE for cheap.
Now, when people trash talk stroked LS2's based on dyno numbers there's a factor to it that people don't understand. There are intangibles to having the larger engine that you just don't see on a dyno. It is more powerful everywhere, all the time. Part throttle power and driveability is better and stronger. Throttle response is stronger. They hit harder. Bigger cams drive easier. Average power is going to be WAY better as well. Managing the torque in the midrange can be tough with such a light car, but with your widebody and everything else I have no doubt you could handle as much power as you can throw at it.
You're making fantastic horsepower with the LS2 already and honestly if you keep your top end and you build it into a 402 I wouldn't put the expectation to gain toooo much peak power unless you really get after the camshaft. What you would gain is at least 40-50 ft lb at the tire and the car would be a freaking animal. If built right it can be very durable - I'm at about 22,000 miles and showing no signs of wearing out - and I beat the crap out of it.
