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The gearbox should be good for about 500hp, after that your living on borrowed time. There are some replacement gear sets, or you could nitride your gears to give them extra strength. Anything more than 500hp will severly push the limits of the drivetrain.

See'ya:burnout:

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You will definately need a decent clutch, the driveline should be fine as long as you are not into hard launches, which I assume you are not into if you are chasing bottom end and a nice wide torque curve.

The only reason I say the rb25de head instead of the rb25det is that the det has vvt on the inlet, and if you want torque, your best off getting cam gears, therefore de head rather than det.

Something else to think about - if you get head and block, you can get the work done - which will take weeks- while your car is on the road. To fit the 3040, you will need a custom manifold and wastegate and a new dump pipe - so the stock one wont be of much use to you. Ultimately, being stuck with a whole heap of parts isnt much use to you - IMHO it would be alot easier to sell the old motor as compete as possible, you could even take a prospective buyer for a test drive and let a mechanic check it out, then when the other engine is ready, swap them over.

I am absolutely not saying that you need to use the rb25de head instead of the rb25det, just some food for thought

steve

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The rb25de head has slightly more aggressive cams, and although they would be replaced in the end they might be a bit better in the short term.

500rwhp, but hard lauches with slicks will kill it sooner than that. A minimum of a twin-plate clutch will be needed.

See'ya:burnout:

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hahaha... thank Merli. I've got an OS Twin in there now and it's sweet. Don't know if i should delve into the RB30 block. At the end of the day i'll be up for some $$$ doing the clutch and gearbox all the time. I might do the Skyline up nicely and get a buzz box like an RX3 or R100 13B Turbo.

With the oil galleries on the RB25DET head, are they the ones for Variable Cam Timing? Is that worth keeping for the trouble of doing all the welding and drilling etc?

Thanks Steve, i'm on there now having a look!

Andrew

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Merli,

I have the same feeling about the triples, great if your never going to drive the car on the street, but useless if you are. My OS twin is sprung and is very easy to drive, but twins will still take a pounding, but I think I'd rather repair it than drive with a triple.

See'ya:burnout:

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Merli, your not the first guy I have heard making similar comments about triple plate v's twin. Hoping I never have to go down that path.

GTS-t VSPEC, I think that one of the gtrs SST have built with approx 540hp (at the wheels?) uses a hks twin plate, but that is a circuit car - spose it depends on how hard you drop the thing off the mark, have you tried to 'drive' off the line like they do with huge hp gtrs? I'm working on that myself, and if you get it right you can get off the line very quickly - even a bit easier to control wheel spin. Might save you a box rebuild too, once the hp starts rising further? I am currently running a 9 button ceramic ferride with 2500lb pressure plate and at 203rwkw havent had the slightest sign of slippage (probably a bit early) - hope it holds on a little longer......

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Steve,

For the drags I have been slipping the clutch rather than dropping it, it is the slipping which kills them. I know the car you are talking about, and agree that a twin is ample in most cases, even if it need the occasional rebuild.

See'ya:burnout:

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