VH Upgrade from Six Cylinder to V8

[Lionelgee]

Hello All,

After regretting selling my VH Vacationer wagon that came fitted from the factory with a V8 and a manual gearbox. I might have found another VH wagon to buy. The new to me wagon is fitted with a six cylinder.

How big a trauma would it be to replace the six with a 4.2 litre V8? Also, is the manual gearbox the same between the six or the V8?

The bloke selling the car says the car has a M21 4 speed gearbox currently fitted to it. It has been a long while since I have had a manual gearbox in a Commodore, so I cannot recall what box was fitted to the six cylinders. My last two Commodores have been autos with 3.8 litre V6s - I really miss the burble of the 4.2 litre when downshifting. Not really interested in going to a 5.0 litre though - or bigger. I went from the VH to a VN sedan and have had a VY wagon since 2015. I want a toy to play with and get back to having a V8 again.

Kind regards
Lionel

 

[vc commodore]

Change some of the front wiring loom, as there is some of the loom for the engine is in different spots 6 to 8's

Radiator needs changing. Outlets are on different sides

Gearbox input shaft is longer on the V8 compared to the 6

Tailshaft is the same providing you don't change diffs

 

[Lionelgee]

Hello VC Commodore,

Thank you for the detailed reply. Is it better to go for a Red 253 or the Blue 4.2 V8? Which is the more versatile of the two?

So no major changes such as replacing the front suspension, cross members or engine mounts - as in major structural stuff?

Kind regards
Lionel

 

[vc commodore]

Blue 4.2 is the better as that's what the VH came with. Saves roadworthy issues

Front springs might have to be changed...If you keep the 6cyl springs, it will lower the front, but not low enough to be a roadworthy concern

Cross members are identical 6 to 8

Get the engine mounts to suit the 8

Brakes are the same, 6 to 8.....4.2's came with drums on the back, as well as discs

You can go for discs at the rear, which then throws up the issue of tailshafts...

 

[Lionelgee]

Hello VC Commodore,

My major concern was structural things like cross members being different. I am happy that they are the same between the 6 & 8. One step closer. Just hope no one swoops and buys the car before I get to inspect on the weekend. Fingers crossed!

Regards
Lionel

 

[vc commodore]

Hello VC Commodore,

My major concern was structural things like cross members being different. I am happy that they are the same between the 6 & 8. One step closer. Just hope no one swoops and buys the car before I get to inspect on the weekend. Fingers crossed!

Regards
Lionel

Got rellies in Bundy...Might have to let them know....

Just kidding about letting them know

 

[Jeda]

Hello VC Commodore,

Thank you for the detailed reply. Is it better to go for a Red 253 or the Blue 4.2 V8? Which is the more versatile of the two?

So no major changes such as replacing the front suspension, cross members or engine mounts - as in major structural stuff?

Kind regards
Lionel

Hi Lionel, any reason that you're going for a 253 over a 308?

It's just that if you're going to do a conversion, why not go for the 5.0?

 

[Lionelgee]

G'day VC Commodore,

I had better change it to a less precise location - somewhere is Queensland might be better!

Kind regards
Lionel

 

[Lionelgee]

Hi Lionel, any reason that you're going for a 253 over a 308?

It's just that if you're going to do a conversion, why not go for the 5.0?

G'day Jeda,

My original car had a 4.2 litre and it never had any issues. So, I will be happy with that. Whatever 4.2 I get it will be kept pretty stock too. Okay, some of the anti-pollution crap might be accidentally eliminated after a roadworthy inspection! The joys of not having to do annual inspections!

Kind regards
Lionel

 

[VS 5.0]

If you want it road legal, you can't put an older motor that pre dates the vehicle in it.

So red no, blue yes.