GTSBoy

Oh, I just realised something.......the Neo DET used RB26 rods. There is therefore a difference in the height from the pin up to the piston crown on the Neo DET pistons compared to other 25s. Not the same as vanilla RB25. I have no specific knowledge of the Neo NA....but I would not expect that they used the 26 rods in it. So, if your plan is to put pistons that you order to suit a Neo turbo onto rods from either the vanilla 25 or Neo NA....I would expect them to not work. More research required, and potentially you will be better off ordering pistons and rods, or some other piston.

75-80 refers to the viscosity of the oil in "winter" and "summer" respectively. It's a multi-grade oil that changes its apparent viscosity with temperature. When its cold, it acts as if it's a little thinner (the 75) and when it is hot it acts as if it is a little thicker (the 80). The other oil has a wider difference between cold viscosity and hot. So which one you use might depend on where you live and/or how the car is used. If you live in a cold part, you might use the 75-80. If you live in a hot part or the engine and gearbox get driven hard for extended periods (and so dump a lot of heat into the oil) then you might choose the heavier oil. As you say, if your box is in good nick, there's no need to put shockproof in it. Just use the VMX.

Followed by compression test. The last thread like this ended up being a broken piston.

I can't speak for R34 conversions, but my auto to manual converted R32 has no difference between auto and manual brake pedal height (ie, comparing my now manual pedal in an auto chassis vs a manual pedal that was always in another manual car). And it is an excellent height for heel & toe, subject to the caveat that I am old school and use the "roll the foot sideways and press throttle with side of foot" technique and not the "swivel the foot on the ball and press the throttle with the flat of the heel".

Worst case you take off cam covers. Plus what Ben said.

coils

I'm sure it's been done dozens of times.

I think you would struggle to get an R200 into an Evo. The Evos are only R180 equivalent or something similar, and they have weird-arse moustache bars for front mounts and so on. They're different enough that it would be challenging. Having said that.....I do know of some Evos having had other bigger diffs grafted in. Just not the details. I tend to think that there would probably be better diffs available from much later Skylines and other Nissans and Toyotas, than the old jiggers in R chassis cars.

Well, if you're going to go down that path - given that the cam profiles are barely different between turbo and NA, and given that the turbo pistons give more combustion chamber, there should be more clearance. And if there is not, a trial fit up will tell you whether you need to mill a couple of spots on the pistons. I would bet $500 that there will be no issues.

It's worse than that. There's a whole niche of late Stageas with engines that are about half-half vanilla and neo and I don't know what's inside them (ie, do they have the RB26 rods and N1 oil pump? Do they have the solid lifter head?).

Or you drive an ALFA and have not renewed the synchros in the last 6 months.

Neos are solid lifter. Injectors are top feed. IACV is different, etc.

With a good ECU and good tuning you are going to make exactly that. Moderate power, nothing too crazy. With the high comp pistons. It's not as if they are HIGH COMP. The compression ratio is still sensible enough for decent boost. I wouldn't change the pistons for this build.

Well, in the specific case of that car, because it is a DET Neo, the bloody great traction control motor & throttle on the crossover pipe is the main giveaway. In general; The plenums are different shapes. Neo is more "square". Little detail differences like location of coolant bleeders, type of IACV, etc. There's an ECU boost sensor on the top/rear of the motor on Neos. Injectors are top feed. Turbos have OP6 housings, but of course this is easily changed. The ECU is a bloody big giveaway if it is still in the car too. Part numbers don't really lie.

To answer the question about swapping stubs. No. BK's info above is that the ALSD has equal length splines. The VLSDs have odd lengths (left to right). No go. The best mech diff centre to buy would be the Nismo Pro. You could probably make a decent job of it by buying to suit a Skyline (5 bolt) and putting it all into the S15 housing. The Nismos come with new stub axles. Your problem with driveshaft lengths may or may not become a real problem. They are splined into thehub end, so you can get away with quite a lot of "wrong length". Just so long as you have enough engagement (not too short) and they don't bump up hard against the shoulder (not too long).

I have vague memories of people needing to use Ferrea's retainers etc. Shouldn't need springs though.

I would think that either of the R32 RB20 cams should go in. The different lift should be taken up by the hydraulic lifter. But, now that I think about that, you'd really want to ask an engine guy if that's true.

The active diff is worth precisely nothing. The problem with the 3x2 diffs/axles is that the CVs in them are tripod style, not proper CVs like the 5 bolters. They are not quite as good. Still reasonably strong. I have them in my R32 (because I'm using an S15 helical centre in my R32 housing with an R34 4.11 CW&P gearset) but I wouldn't try it with lots more power than I have (only ~200rwkW). The reason to use R33 turbo diff is that the NA diffs are the same 3x2 stuff as the S chassis diffs. And they are open (not LSD, not that it really matters if you are going to replace the centre anyway - but keep in mind that the open diffs have equal length splines on teh stub axles, so you can't use the exact same aftermarket centre in them in many cases).

I guess the ALSD must be wider to make some space for the crap they have to put into the sides for the clutches. I'm surprised by the length difference. This is yet another reason why "all R200s are not the same as all other R200s". Your best bet would be to obtain another R33 diff. Just a regular VLSD out of any turbo, auto or manual. That housing will give you want you need + the required stub axles. Then you just buy your mech LSD centre to suit. If you buy Nismo, it will come with new stub axles (equal length, to replace the unequal length ones that live inside VLSDs), but if you buy KAAZ, or Cusco etc, I think they reuse the unequal length stubs. The 5 bolt driveshafts you show look the same as any other R chassis shaft, so they should fit to any 5 bolt stub. I would not assume that the CW&P on the active diff is the same as the others. There are a few ways that Nissan have done that differently - mainly thickness of the mounting flange and bolt diameter. This won't matter if you don't try to use that active diff for anything. If you get another R33 diff you should be able to move the 3.7 gears across. You could dismantle these though and work out what is what for yourself. Worthwhile exercise IMO.

It's not a GTR diff. GTRs have 6 bolt axle flanges. Not the 3x2 = 6 bolt flanges like your S chassis diff. 6 evenly spaced bolts, on "ears" like the 5 bolter pictures. GTRs also have a CV joint type input flange, not a flange to pick up a uni-joint. Follow the wiring loom in the car body that would plug into that connector on the top of the diff. Find out where it goes to. If it goes to a CU up in the boot somewhere, then the car looks like it had an active diff. I've not paid any attention to active diff R33s, because they have AIDS. But for all I know, they might have different flanges. Show a photo of the matching end of a driveshaft so we can see if it looks normal.

Nope. Leak must be pretty small though to be able to be compensated by timing (assuming that's what's happening).

Normal 5 bolt R200 stubs are 5 bolt with spacing much like what your picture shows.....but your flanges look too round. Just look at the flanges on this lot to see what I mean https://www.google.com.au/search?q=r33+diff&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiRgMnZ2d3jAhVFWysKHWHVBicQ_AUIESgB&biw=1519&bih=819

Nismo are barely stiffer than originals. Buy originals or Nismo - whatever you can get your hands on. You car is a HICAS car, therefore buy the mounts to suit a HICAS car. Doesn't matter if it was there and is now deleted. The removal of teh HICAS won't change which engine mounts it has.

Always call a Jack a Jack. Always call a spade a spade. But always call a whore a lady, because their lives are hard enough as it is.

That would be A-LSD, not V. But yes. Notwithstanding that....the side flanges are odd. Did the active diff cars have different axles in some way?