408 horse power?
That doesn't surprise me but what did the torque do?
I can only give you an indication because it was a chassis dyno, not an engine dyno.
Basically it moved peak Tq from appx 3900 to 4500...and the figures stayed around the same. (Est. Peak hp of 420 is at 5500 currently)
What this told me was that the Tq that these SB strokers make is so much more than the std stroke equivalent.........the old rules about Single Planes only being for revvers just don't apply to them.
In fact, the strokers "need" a decent size runner and plenum like you'd find on an M1 SP (or an Air Gap).
The older intakes just can't feed them.
To be fair, I run 3.89 gears so streetability wasn't effected either.