Current engine is the stock 2.5L so I would think the springs will need replacing as the is a weight differential between the two engines 190 lbs. The 2.5 weighs 240 lbs and the 327 weighs 530 lbs.
I've got a 2000 TJ with a gas guzzling 2.5L that suffers from a lack of power. I also have a 1968 Chevy 350 paired with a TH350 trans. How much lift required suspension/body? Can the TH350 mate with the TJ transfer case? The stock differentials need replacing too.
My 2000 TJ with its 2.5 L Inline 4 cylinder gets in the neighborhood of 17 MPG. I've been considering updating the engine and tranny/transfer case to achieve 30 plus MPG. Or is there some updates to the current configuration to improve the MPG?