the rody is an on-road engine.... bad idea IMHO.

the picco 28 is really fast and if you get it modded it can go faster than any rb. it comes close to a os 28 truggy race black head. a modded picco goes so fast it makes savage transmissions explode but i wouldnt worry with a firestorm as its only 1 speed.

i have a mach 427 in my savage and it runs well.

if you dont want to go with modding then i would get one of the OS truggy race engines.