77 4speed to 81 5speed

[Guest Anonymous]

I heard a while back that if i swap my 4 for the 5 speed that i would need to switch rear ends also. Im just trying to double check on this before i go through the trouble of taking out both rear ends. Also any advice on a clutch upgrade for the street.

Thanx:cheers:

Steve D

www.my 280zmail@yahoo.com

[Guest Anonymous]

No need to change rear ends since your early standard Datsun 4 and 5 speed should be very similar in gear ratios with one (5 speed) having an extra over drive gear. I put a 4 speed from a pickup in a 280 Z once and found it was fairly snappy in second gear.Years ago, many people believed that automatic transmissions and manual transmissions required differeft rear ends for gas mileage and power reasons

[Mike C]

You don't HAVE to change rears, but the '81 5 speed first gear SUCKS! It's like 2.8 vs. the 4 speeds 3.3 3.3*3.54=11.682 and 2.8*3.54=9.912 or nearly 20% reduction of gear ration in first gear. Changing to the 3.90 gear will help, but will reduce the overdrive effect if that's what your goal is. I put a '79 5 speed in my car which has the 3.0 first gear and went to 3.54 from 3.36 reaar gear, but it still lacks the snap it had with the 4 speed. THe solution is the T5 which has a 3.27 first and a better overdrive, but they are harder to find and more $

[Phantom]

Steve:

I have a '77 that I swapped out the 4-spd and 3.54:1 differential for an '83 5-spd. and 3.90 differential. If you go with the 81-83 5-spd. you will need to do the differential swap or your car will accellerate like a slug. The new combination will give you equivalent accelleration in 1st & 2nd to the old 4-spd. & 3.54:1 but will be noticably stronger in 3rd & 4th with 5th for a really nice cruising gear. You have the best transmission but don't ruin it by not changing the differential to the 3.90:1.

Phantom