Originally posted by afm
If I'm not mistaken, R Spec is ROAR/IFMAR spec, which means cranckshaft could have bigger inner dia. (8mm), and turbo scoop can be big enough to come from inside hole.
E spec must be EFRA spec engine with crank inner hole limited to 7mm without chamfer and turbo scoop doesn't meet hole.
Sleeve porting, timing, and rest of engine must be the same.
AFM
thanks bro for that update on the difference between the 2 engines. as for power difference, which of the 2 has more power???