3LT out 4.2 in

how many k did you get out of the RB30? what is failing?...silverback

Not sure if it will as I have read that the drive trains in the 3liters were lighter than the 4.2's hence the lower towing rating.
People to ask would be engine conversion mechanica I would think.

pretty sure both the gearbox and diffs ar lighter duty fort he petrol 6 certainly the gearbox will be i think they are out of a 300zx.
Unquestionably the cheapest way to do an engine swap is buy the vehicle you need

Why not try for a RB30ET, the turbo motor from the VL Commodore. Gives you the extra grunt you're after without the hassle of too much conversion work

Hello,
From my own recollections the rb30 has a lighter gearbox than the 4.2 ltr.
I would respectfully suggest that it would be cheaper to sell the current GQ and invest in the purchase of a 4.2 ltr if thats what you want. Given its age I would consider that you would not get any money back that you spend on your current car by changing everything over.
I think the diff ratio's are lower too which means higher revs at cruising speeds.
Best of luck
Alan.

From a purely economic viewpoint, I reckon it would be throwing good money after bad.

If the thing is knackered dump it and update, it will be cheaper.

And I'm speaking as one who owned an RB30 GQ and loved it.

Jim.

The power/turque of the 4.2 motor may well rip that gearbox to bits.

I'm no expert, but think of the logistics

Basically a car gearbox, replaced by a genuine 4B motor,,( even though its petrol )

When you are asking it to give a bit more, one day, something will give,,

Then again it's your money $$$$$

Cheers
Bucky

As an owner of an RB30 GQ I have investigated this also.
My RB30 has 375,000 on it and still going strong.

The gearbox you have has an integral bell housing and not interchangeable with the 4.2.
From the transfer case back all is OK. I have a mate that had the same setup and he replaced the engine and 'box with a 350chev and 4.2 g'box. Nothing else major touched. Topped out a bit early but on went the bigger tyres and all has been fine. It had about 300,000klm added after the change of mostly rough tracks and dirt roads. It has now since terminated with the body succumbing to fatigue and the rear suspension also going south. (carrying too much load constantly)

I am still pondering on simply replacing the engine with a VL or going whole hog and slotting in a BF motor and auto. But at the moment things are sweet so I'll just wait a bit longer. The Chev is just too thirsty.

Cam

Thanks everyone...for the input...i was just hoping to find a way to get some more out out of the old girl .as have spent way to much on her ..as we all do..but all running gear and most other things have been replaced within the past year ...so apart from the donk....its a good jigger...and with the hi miles need that little bit more top end power
Cheers Bundy