I recently purchased an RX2 for racing in vintage class. The car is an old race car that has the original twin dizzy engine. I think I can swap-in a later year 12A from an RX7 and still be OK with the rules. Is there any particular value to a twin-dizzy 12A that I should "save" this engine (or sell it) and race with a later 12A ?

 

Most vintage groups will allow the later 12a without issues, I don't think I've even heard of them being singled out except for porting rules that come from when the were raced originally.

Definately run the later engine and keep the twin dizzy for future options. I have the same situation. I have 2 twin dizzy engines in parts that I might just put one together for a special event for historical value but I'm going to run a full tilt monster 12A most of the time.

What is your car's history? Mine ran in the IMSA RS series and SCCA B Sedan.

 

I picked-up the car in New Mexico. As far as I can tell, it was a "track car" used for SCCA events approx 20 years ago, and sat since then. No class markings, but it's gutted, caged, racing seats, numbers painted on the doors,etc..

Thanks for the advice on using a newer 12A. I am planning to run "VARA" events http://www.vararacing.com/

B SEDAN
Included are 1972 and earlier cars eligible for SCCA BS class and TransAm. This list may not include every possible eligible car.
Alfa Romeo Sedans up to 2 liters
Alfa Romeo GTA
Audi 100
AMC Gremlin
BMW 1600 and 2002
BMW 2500 sedan
Chevrolet Vega
Datsun 510 and 610 up to 1800cc
Fiat 124 Sport Coupe
Ford Cortina and Lotus Cortina up to 1800cc
Ford Escort
Ford Capri up to 2 liter
Ford Pinto up to 2 liter
Mazda RX-2 and RX-3 non-bridgeport motor
Opel Kadett and Manta 1900cc
Toyota Celica
Triumph T2000, 2.0 Vitesse, 2.5 PI saloon
Volvo sedans up to 2 liter

 

From my own experience...

The newer 12a parts sell faster and for equal or even more money.

Personally though, I feel the twin dizzy motors are worth more for nostalgia reasons. I tried to sell my twin dizzy a few times and wasnt getting offered anything worth while. I decided to keep it, clean it, and shelf it for a garage trophy...