426 stroker kit
Yeah, there are some guys getting miles out of the longer strokes, but I don't know the condition of the components inside and I've also heard many horror stories and have seen the pics to go with them. Primarily has to do with the thrust side of the cyl. walls.
I tend to go with what the Chrysler engineers work out, as they have high standards for longevity and I have no clue what standards the crank manufacturer's "engineers" use. They may just be using a stroke that has worked for them on a chevy engine or something. To me, it's like buying a cam that fits a Mopar but was ground with a popular chevy grind.
For my Cuda, I went with the 3.795 Scat crank for a 392", as that is the crank Mopar Performance used for the 392 crate engines and drag pak engines. To the contrary, I noticed Chrysler backed down the stroke a little on the regular production engine (again, to achieve greater longevity on a high production engine?).
In the 426 crate motor, they used a 4" crank (I believe it's from Callies) and that was even with the aluminum block. I know there are guys running 4.125 cranks out there that put out good hp and mega torque, but the ones I'm familiar with didn't last too long. I know of one guy who built an aluminum block with a 4.125 crank, but built it for one particular race event and then refreshed it / sold it right after.
People don't often explain those situations, so you just have to read between the lines and come to your own conclusion.
I know there are a few 4.08 crank 6.1's with over 50K miles and one with 80K. The deck height doesnt like the longer stroke when things get into stupid power, like 800+hp with boost. A 4" vs. 4" +.050" isnt gonna make or break a N/A engines life span IMO. If you want to turn 8000 rpm+ I would stick with a 3.79 or stock stroke.