Hi!
I have a 427R in my Superformance and i am happy with it.
More or less no
oil consumption, runs strong, good torque.
At the beginning ist was no fun to drive below 1.800 rpm - after some
problems with the carburator i changed to a QFT - at the Moment i have
some stumble below 1.500 rpm but i am still not at the end to optimize
the carburator - think at the end it will be nearly perfect. The stumble on most
427R have to do with lean condition under low load - so it has to do with the
Tuning of the carburator - in most cases the carburator is tuned for high HP at
the Dyno.
However i think the 427SR will be the better choice cause of the more street
friendly cam. And i am not sure if you will notice the difference in HP in reality.
But think with some Tuning on the carb you can not go wrong with a 427R too.
And both are lots of fun :-)
Till now i have zero Problems with my 427R and i drive on the spirited side.
But when i would buy a new engine i think i would not buy a Roush. With all these
high HP engines some things can go wrong - then you will have to fight with things like
customer Service - some years ago Roush was very good in these things too - but seems
this times are over.
Take a look at Brent Lykins - his customer Service is terrific - really a great guy!!!!
Do not understand me wrong i would not say that the engines from KC or Brent are better then a Roush but when it comes to Problems the there will be a huge difference.