Originally Posted by 02Toyowrx
R4 has thin cylinder walls..106mm i think.. bored to the limit.... I would suggest using crawfords S4 engine. And compare pricing and timeline with Axis.
Reall? Where did you hear that?
This guys running 500+ on his 2.8
IMO the s4 isnt compairable to the r4. The R4 has replaceable Wet Sleeves, squirters and is going to need more air flow from the heads.