i would always tend to recommend an engine that is very close to the same year as the chassis so that all the ancillary systems are more likely to be compatable.

i think that the early 3.5 motors are known to be quite stout in the power department. durable too.

the trick is finding a good used one to put in. it might be as easy to find a good 280 motor.

the newer engines will physically fit just fine i think. the 380 and 420 are pretty much identicaly i think in size shape etc as the 3.5 but with aluminum instead of iron blocks.

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.