Hi Anyone. June 12, 2004

My name is Roger. My wife and I have owned a '72 Datsun 1200 for 23 yrs. Great car. People want to buy it all the time. Recently instqlled our third engine. This time an 1979 remanufacued A12A; bought it from an engine shop; was sitting on its on pallet and plastic wrapped. Didn't know its perferral parts were different locations than our original A12. Anyway we have it running.

It has always had a 3 speed automatic and we want to change it over. On the Southern Califonaia freeways running at 75-80 mph the engine must be reaching 3.5-4.0 thousans rpm's. We want it to run at about 2.5-3.0 thousand rpm's traveling between 75-80 mph if possible. Use car for business.

I found a '79, 210 station wagon with an A15 and having a 5 speed; odomewter shows 120,000 miles. Car in good shape. Also found an '80, 1200 sedan with asn A15 but an automatic.

Question we have is which trans and dofferential would be the easiest to pull and attached to our '72 ? I'm thinking the A15 with the automatic has a better gear ratio in the differntial to handle the A15 so that might the eaiest to change ? What about just taking the diffential off and putting it in ours. Would I also have to remove the rear axle and switch them as well.?

Any suggestions would be appreicated. thanks you,

Roger and Charlene Seymour .

What body type are the diffs coming out off?
Normally station wagons havea 4.11 whereas coupes and sedans have 3.9...

Hi Roger,

I did a similar swap (1980 Datsun 210 A15 engine and 5-speed into my Datsun 1200).

Quote:Neither.

Engine: easy swap. The A12A and A15 have the same motor mounts.

Differential: the "Datsun 210" is a B310 chassis. The rear end is coil-spring, so it's not a direct bolt in (the Datsun 1200 has leaf springs). However, reportedly the third-member (differential center) will interchange. It likely has a 3.7 ratio whether auto or manual.

All US Datsun 1200s come with a 3.90 ratio.

Transmission swap: The "best" swap is to put the five speed in -- and keep the original differential. The first-gear is taller and the overdrive will drop the revs down significantly. But you have to:
- convert the 1200 to clutch cylinder and clutch pedals (find a 1200 to get the parts from)
- (perhaps) find a 1200 manual driveshaft
The 5-speed is the same length as the 1200s 4-speed.

If you keep an automatic and lower the gear ratio the engine will have less get-up-and-go. But it will lower revs only a little bit at highway speed:
3.9/4000 rpm ~ 3.7/3800rpm

A 210 with A12A, 5-speed and 3.7(?) ratio got up to 47mpg highway (per EPA) ... while a 1200 only got 38mpg highway (claimed by Nissan).