What ratio would you guys suggest? It's 13b turbo with a 5 speed 245/35/17 tyres and hilux diff.been told around 4.58s but there just hard to find

For the quickest acceleration, get the steepest rear axle ratio you can find. Since you have a five-speed, you will still have good top end speed.

Or for economy, use any typical ratio. 13B used 3.9 gear ratio from stock.

Okay makes sense.when I mentioned this to my engine builder he said 4.1 will feel like its taking of in 2nd gear?so surely 3.9 would be like taking of in 3rd gear?

3.9 feels like taking off in 1st gear of a factory RX7 13B (they used 3.9 gears).

But a standed 13b isn't Bridgeported and making 450hp.sorry probly should have said that

Does it makes power high in the RPM range, and little power down low? Then even more so you need the steeper gears.

The power ouput has less to do with diff ratio selection than the intended use.. If its for circuit racing, the ratio to be chosen will vary with the track and is also dependant on gearbox ratios and RPM limit.
Eg. the fast bridgeport rotaries in Vic use a 5.1:1 at Winton(max speed of 195 at 10,000rpm). At Philip island they use a 4.1:1 (max speed of 255Kmh).

If its for the road, i`d personaly choose a ratio based on where the engine power starts to smooth out(usually about 5k on a good bridgeport?) and 110 KMH in forth gear. Otherwise is will be a pig to drive at cruise on the highways.

450 HP? Is this thing a turbo BP? cos the best race BP`s ive seen make less than 300hp.

i used to run 4.88 in my 12a bp ute and with 195/50/15 tyres it used to run at over 4000rpm in 5th at 100kph
with your taller tyres it should rev slightly less.

id say 4.8 - 5.1 if you want it to launch hard, 4.1-4.3 if you want it to cruise nice

so yeah, 4.5 will be a happy medium

Okay awesome guys.is a street car and yes is turbo