I'm not Rooman but i'll try and help.
Why do these engines have so much cackel to them seems like the modern fuel motor idles more tame or am I hearing it wrong! Love it when they burnout then it comes back to idle
--Modern fuel motors have so much fuel volume that the cackle gets lost i believe. I miss it. Just another reason NTF is where it's at!
Also what width wheel do they use i know the tire is a 12in. spec for the class but looks like maybe a 10 in. wheel
--They run a 12" wheel also. Some teams take advantage of the 13" tire (both are legal)
Also A/Fuel does the injected cars run nitro and blower alky??
--A/F has injected nitro or Blown alky. both sound awesome, and both haul butt, however it is a never ending battle to level the playing grounds.