sir 3F engine is a fuel guzzler, you will always be needing a fuel bowser following you when you decide for an off terrain adventure.
if you have enough resources to spare please source 1KZ diesel engine from KPK and swap it.
another choice can be a 1FZ-FE petrol engine a bolt on swap without change of transmission as well.
you can wait for more input from veteran RKR users of PW