78 or 82 5 speed

[ricksaia]

Hello everyone. I have a 1970 240Z with a 2.8 (f54), a p79 head and an 82 r-200 dif. My question is, do I use the 1978 or 1982 5-speed I have sitting in my garage. The 78 may be better off the line, but I may get better mpg with the 82. By the way, I have already cut the hole in the trans tunnel for the 78. Let me know. Thanks, Rick.

[sblake01]

It's just a matter of prefference. Lower 1st gear or higher 5th gear. I have a 82 trans in my 78 and it requires no modification which is to say the the hole you cut in your 70 would work for both of them. Unless the ZX trans is a T5.

[Victor Laury]

Rick, I'm ALMOST certain that the 70~71 shift hole mod would be the same for both transmissions.

#1 priority - Which trans do you have the most confidence in as far as condition?

[ricksaia]

Both trannys are in great shape. For everyday driving, I want to choose the one with better off the line performance. Let me know. Thanks. Rick.

[sblake01]

The ratios are as follows:

78 (FS5W71B) 1st-3.321, 2nd-2.077, 3rd-1.308, 4th-1.000, 5th-0.864.

82 (FS5W71B) 1st-3.321, 2nd-2.044, 3rd-1.408, 4th-1.000, 5th-0.752.

Off the line performance would be about the same though 2nd in the late trans is slightly higher, and third is lower. I really don't notice much difference in second and my car pulls slightly better in third than the stock trans but that fifth gear drops the engine down to a nice low cruising rpm on the freeway and does yield better gas mileage. And added plus is that my stock trans was cast iron and the late trans is aluminum. Anything that saves weight on a 280 is a good thing!

[NH-75-Z]

I recently changed the tranny in my 75-280 from

4 spd to a 78 5-spd.

Although the 5th gear is "better" than the old 1:1 ,

I had expected a lower RPM for Highway cruzin. Its

3K RPM at 70MPH +/- (3.54 R200 ) .

So since both 1st gears are same ratio, I'd suggest the

82 Tranny !!