Assume factory-spec automatic transmission, stock or same rear-end gears, and optimum fuel/air mixure and flow.. Is the smaller 2.5 L offset by the heavier 280 body. Assume coupe or sedan... no wagons.

Which years are the best for each? What simple bolt-ons are there? Does limited-slip differential play a role? Are there higher gear-sets and does it take a specialist to swap them? When will I stop asking questions?

usually the car with the bigger motor will win the drag race.

limited slip wont matter on these cars. it will only make it quicker if it has enough power to smoke the tires.

there are generally several choices of diff that can be swapped in if you want to experiment.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I'd go with the 280, there were a lot more of them made, so you won't be thrashing the rarer motor. A 250 car with a replacement 280 motor isn't worth as much as a original 250. There is that whole displacement bonus too.