The reason the distributor is in the rear is because of the oil pan layout....a rear sump suggests that the oil pump is in the rear and the small block designers wanted to drive the oil pump using the distributor shaft....hence both needed to be in line and at the back of the engine. The reason that a Chevy had the individual rocker arms is because they were trying to take money out of the rocker shaft design...a benefit they didnt plan on was the rev potential of the lightweight valve actuation system.

mike in tucson