Is it possible to put a 3lt into a 4cyl engine bay. (without changing the chasis)

I believe you have to move the engine mount on the LHS chassis rail forward. In a 4cyl the power steering reservoir is in front of the mount, in a V6 it's behind it.

why bother??

Sure is possible, you would need a V6 TR/TS body to get the parts needed of tho. You will need the sub frame, engine mounts, radiator, transmission, cv's and if your unlucky i may even need the brakes. its a tall order

Well thats a bit to much effort.

Screw it

If you were to even consider this, a better option would be the DOHC like killbillys, you'd basically have to replace everything anyway. Oh and yes you would need to upgrade the brakes for it to be roadworthy.

Sell the 4 cyl and buy one one with a 6 in it that's what I'm doing. The best thing is that they sell at about the same price.