Need some advice on pinion angles as I have a bit of vibration.the box points down a little at about 4degrees.what angle should the diff be? Iv read they should be parallel for the unis to cancel each other but adjusted to that today and it was much worse vibration.adjusted again and put diff about 1degree nose down.it does seem better tho.am I going in the right direction?

Yes they need to be parallel so pointing the diff up to about 3deg is where you want to be to allow for the diff nose to point up under load. Remember they also need to be parallel on the other plane too ie. if you draw an imaginary line through the middle of your car your engine/box and diff need to be parallel with that line. They are allowed to be offset but must be parallel if that makes sense.

If you've been running with incorrect angles there's a good chance your uni's are already shagged so have a good look at them aswell to avoid chasing your tail

Good luck

It has been fine only a little vibration in 4th.as I said I moved diff angle up to match the box but it made it much worse so I went back to how it was

Make sure it's straight the other way (front to back)

Yep it's also straight mate.not sure what it is.had it all setup as per text book yet it was worse then not text book set up

its possible that the cause of the problem is elsewhere and that adjusting the pinion in some ways can make it seem less apparent.

ive set up 2 different 1200's with engine conversions (12a rotor & sr20) in the way i described to you and have taken them both
regularly up to 200kph on racetracks without any vibrations at all. both cars had vibrations before i adjusted the pinion.

personally id be setting the pinion angle to 1-1.5deg less than the engine/box angle, making sure its all straight (parallel) front to
back and if theres still vibrations id be checking the rest of the drivetrain, but thats just me.. im no expert

let us know when you find the cause, these sorts of problems are always difficult to diagnose... best of luck

you can have your diff angle at 10 deg if you want . my mate racing a off roader an he has 20" of travel with a front engine an the tail shalf is about 800mm long. it's your diff or gearbox .I have got the same problem with a rotay Datsun staionwangen