Pistons hitting anything should not be an issue as they aren't coming out of the bottom of the sleeve any more than a 4.000"/6.125" combo.Lot's of issues with one being cylinders are too short to adequately guide the piston at TDC and you would have to have a custom crank made as well as 6.000 rods wouldn't clear. 99% of LS cranks which are cam-cut for 6.125 long rods. Rods may or may not hit cam at 4.250 stroke depending on many factors. pistons might hit main webbing at BDC too depending on piston shape and skirt profiling and design. Crank might not balance without a lot more heavy metal as well.
You have built some stuff similar to this haven't you?
Oh yeah. but 6.0 block only has a 5.450 long sleeve or so so that's not a really good idea in that block.
With an average ring stack of .700 you only have a half inch of piston skirt in the bore down there. not many skirt profiles like that to say the least.
Internet is very very spotty at my shop right now and still no regular phone so it's hard to even get on here most of the time.
We did some drag race only that had 2 ring pistons that were NA and they ran vacuum pumps. It was an .043 top and 2mm oil rail. I think it was only .920 comp. ht.I was speaking specifically about the long stroke stock block stuff. I thought I rember some weird displacement stock block stuff he had built. That had a lot of stroke