The modern Modified Production sedan is quite a technological car as the handling can be improved by adjusting the suspension and changing tyre size and compound, and in the case of EFI cars, engine performance can be monitored and adjusted via the use of after-market performance engine management systems. 

It is not uncommon these days to see pit crews plugging laptop computers into the engines in the pits between races.  Competitive cars can range in price from $15,000 to $80,000, although the average cost would be closer to the lower figure. 

Most cars are built in backyard sheds, although recognised chassis builders do build a few.  These cars are real race cars which have many parts found in higher level speedway cars.

Many good Modified Production sedan drivers have moved up to higher performance speedway classes and have been very successful. 

A Modified Production sedan is a race car based on a four-seat going passenger car.  The original car body shell is utilised and a fabricated steel chassis and roll cage are fitted within the body shell to ASCF Inc. Specifications. 

Removable body panels can be replaced with fibreglass or aluminium replicas but must look like the original panels.  The differential and gearbox must be from mass produced passenger cars and can be modified but must look standard externally. 

Suspension can be fabricated and modified from standard, but must have the same basic configuration as the car originally had, as a road going vehicle.  All suspension components must mount directly to the original mounting points on the body shell. 

Modified Production sedans can use a maximum of an 8 inch tyre (as per markings on the tyre) on a 166mm wide rim.  Engines must be the same make, series and configuration as produced by the manufacturer for the model body shell being used.  Maximum engine capacity is 4.5L. 

Crankshaft stroke must be standard but other internal performance modifications are allowed.  Pre-EFI cars can use Methanol for fuel and a 350cfm Holley Carburettor.  EFI cars must use unleaded petrol and EFI

ASCF Inc. Technical Committee