Derek - Remember when we used to run mod 1/10th pan cars with 8 turns on asphalt....oh wait...you never did that! (You know i'm just bustin on you
) That was the FASTEST class ever. More rip and cornering speeds than nitro 1/8th with similar top speeds. Stock 1/10th Pan cars were faster than open mod sedans on most tracks. Regular guys could not control the cars with stock motors. This class died.
If you look at unlimited racing it always self destructs. F1 in the late 80's, IMSA GTP, Group C Rally. The healthiest racing series have regulations to keep the racing close and limit advantages to big money teams.
RC Driver Gary - Oval cars are direct drive and more efficient. The stock 4 cell oval cars aren't that slow. They also carry a lot of corner speed. There are no 1 foot radius hair pins on an oval. With the gear/belt reduction and associated drag 27T 4 cell sedan would most likely be very sedate. 19T would be a good option.
With the mass availability of good brushless systems drawing near and LiPo batts on the horizon much of this will be moot soon.