Thread: 3.9 to 5.0 litre

Slunnie wrote,..

The casting methods used by Rover were fine for 3.5's but not accurate enough for the motors with bigger bores. The bores that were produced and measured with the most thickness went to the 4.6 and the thinner ones went to the 4.0. This is as I understand it why the 4.0 is more prone to cracking, but all of them are in the same boat.

Hello Slunnie,

Yes I agree. From what I have heard, the new blocks being produced by Cosworth are much better in this regard. No cracking problem....so far..

Ron.

Originally Posted by Fish78

In the words of the Prosche Cayenne ad...

Originally Posted by Fish78

If you have to ask why you need 450BHP to drop the kids off at school your not thinking hard enough..lol

Put 450hp into a rangie and the only things you'll drop are the diff centers

I'm with big guy on this one,it's not that there is anything wrong with a holden V8 but after buying all the parts to make it fit and an engine you don't get much bang for your buck.I'd still go a 4.6 and spend the money I would have spent on adapter kits etc top hatting the block and doing a few performance mods and be happy with it.Putting more power through drivetrains not made for it just causes headaches,the brakes aren't good enough for a stock 4.6 for starters. pat

Originally Posted by RoverP6B

Slunnie wrote,..

Hello Slunnie,

Yes I agree. From what I have heard, the new blocks being produced by Cosworth are much better in this regard. No cracking problem....so far..

Ron.

Not so sure about that. V8 Developments report cases of Cosworth blocks having the same cracking issues. This was mentioned earlier this year on the TVR, BritishV8 and RangeRovers.net forums.

The only sure permanent fix is top hatting, but once done the RV8 will go on for years with no problems in this regard. And if you do the right thing with tuning, it can produce some very respectable power to weight figures.

Originally Posted by Slunnie

Did you mean the 6L80E or the 4L80E?

Just googling around. The 6L80E was in the VE Commodores and WM Statesmans with the 6 litre V8's. The 4L80E in the Suburbans as previous said.

4L80E, don't think you'd need 6 ratios....plus the 4L80 adaptor is available to LT230

Advocates of the Rover V8 must remember, just because they did it (i.e fitted 4.6), doesn't mean they have too knock the alternative options, why poo poo something you obviously know **** all about, have never tried?? I love for an answer

Rover V8 heads can NOT support large capacites effeciently, so your scrwed from there, the last LS1 GU patrol I wired, has a baby camshaft, valve springs 3" single exhaust and a Mafless tune, it made 260HP on 35" tyres, and will return 15-16L/100, let me see your aftermarket ECUd rover stroker do that on 36's

Why convert? stock engine, with a substantial power incease, an ECU with closed loop, timing control, transmission control and you can plug it in at any holden/efi live/LS1 edit tuner

Originally Posted by rovercare

4L80E, don't think you'd need 6 ratios....plus the 4L80 adaptor is available to LT230

Advocates of the Rover V8 must remember, just because they did it (i.e fitted 4.6), doesn't mean they have too knock the alternative options, why poo poo something you obviously know **** all about, have never tried?? I love for an answer

Rover V8 heads can NOT support large capacites effeciently, so your scrwed from there, the last LS1 GU patrol I wired, has a baby camshaft, valve springs 3" single exhaust and a Mafless tune, it made 260HP on 35" tyres, and will return 15-16L/100, let me see your aftermarket ECUd rover stroker do that on 36's

Why convert? stock engine, with a substantial power incease, an ECU with closed loop, timing control, transmission control and you can plug it in at any holden/efi live/LS1 edit tuner

so an LS1 is the same as a 308

Just poohing ya,

the question is - do you think the 308 is a better swap for a propper built 4.6 or 3.9?

Not better, not worse, just different.

Originally Posted by Hardchina

so an LS1 is the same as a 308

Just poohing ya,

the question is - do you think the 308 is a better swap for a propper built 4.6 or 3.9?

No a 308 isn't a worthwhile conversion, but a fuel injected 304 is or better yet a 5.7 or 6.0l

I have a rebuilder 308 here, with all adaptions to suit LT95 if you wanna buy it