Here are the engine/trans rules.
ENGINES
1. Must be in stock location. No engine setback. #1 spark plug must be in line with or ahead of ball joints.
2. Must have cast iron intakes, exhaust manifolds, heads and blocks.
3. No headers. No bow tie intakes. No angle plug heads.
4. One carburetor only. No electric fuel pumps.
5. Stock factory distributor. No M.S.D. ignition systems.
6. All exhaust must be pointed away from the ground, preferably to outside of car
TRANSMISSIONS
1. No after-market transmissions allowed. (ie. Bert, Brinn etc.)
If it is not prohibited in the rules, then it is OK. So basically you end up with a somewhat limited intake exhaust..... but everything else is open to imagination. I know there are companies that can acid treat the cast iron intake to flow a "bit better". I am pretty sure the top guys probably do this and get away with it.
The reason for the year Camaro I listed is because supposedly it has the best front end geometry for a dirt oval car in regard to camber/caster and spindle size. Most guys presently run GM metric chassis, but some do run older Chevelle and Camaro front subframes because of the better front control arm geometry. Front contol arms and front subframe must remain stock.
The middle of the frame/cage and the rear frame/suspension is somewhat leniant and can be custom fabbed 3 bar, 4 bar or leafs. A stock "type" rear end must be run .... Most guys use a Ford 9" floater which is what I would probably end up with eventually.
Here are the rest of the rules from the racetrack website.
2010 UMP Bomber Rules | Oakshade Raceway