Most folks that say go stroker never tried a 340 with 4.56 gears, IMO
Yep W2 heads will wake the 340 up, then even 4.80 gears might be best. As for high rpm's, heck the M6 engine turns 8,000 rpm, who says you can't as well.
Now fuel mileage, LOL, a gear down 408 will get better mpg on long drives and will make a better street friendly driver