I understand the desire and appeal to keep the 440, but the Imperial is a big ol' CRUISER not a drag car. Drop a modern Hemi in it and be done.
That was an early consideration. However, the Gen III suffers from the same issue as the earlier variants. There's nobody home down low. You have to get the revs up to find any torque. It would be a fun motor but similar to driving around a pickup.
As for my OD swap, I do have the lockup trans and converter.
Turbos have been calling me, especially since I still have them but that would be an even bigger distraction than what I've already got in front of me with the Imp and the roadster to follow.
Sounds like you're between a rock and a hard spot. You've got a land yacht you want to accelerate like a mid-size sedan and still knock back decent MPG.
Either big block stroke it and get the down low torque, but with crap mileage, or G3 Hemi it and get the mileage, but no torque.
Have you thought about a G3 swap with a trans that has more forward gears than a 518 (my knowledge of what is available is nil)? Could make up for the lack of torque if you can slide an eight speed in. Bonus, stick as close to OEM as possible and get OEM reliability since you plan on using it as a daily driver.
