You should be delighted with the performance of your Pertronix unit.
Easy install, faster starting, smoother idle & it's a set & forget item

Well that's how it is for me & my stock 1200 Coupe has been running one for years.
I also recomend quality leads & some Platinum plugs. I have opened the gap on mine about 10% as these plugs will fire a spark across a given gap at a given compression pressure at a lower voltage.

Bloody beauty, open her up for a nice big fat flame which will fire the mixture perfectly.

If you are running a carb that has provision for vacuum advance then use it. It was provided by those clever Datsun Engineers for a good reason & I have yet to find a valid excuse to think that I am more clever than they were.

If you want to disconnect something, find out, in detail, what it does, how it does it & why it does it, then have another think about it.

[Disconnecting it will leave your engine running retarded from the optimum position when in cruise mode & that doesn't help anything.]

The standard diff ratio in a Ute is 4,11 to 1 & was intended to help the short stroke, low torque 1200 engine to haul the full rated load that a ute is designed for.

The A14 engine has a 7mm [1/4" longer stroke as well as a larger bore & it develops a very useful increase in torque.

If the Ute is to be used as a toy rather than as a workhorse then a switch to the 3.9 to 1 ratio found under most L series powered models [with live rear axles] will cut the revs without hurting performance noticeably.

Using a tyre with an outside diameter of at least 575mm is also a good idea. I recomend 205x60x13's on the rear as these will help fill the wheel well without rubbing & are readily available at modest cost.
A 6" wide rim is perfect for this size tyre.

The five speed sounds good but is both difficult to obtain & expensive when found, but in addition to the above alterations, it would be recomended because at highway speed in 5th the little sucker will be singing sweetly.

For international members the legal highway speed in most areas over here is 70mph [110kph] not 55 mph [88kph]& I have never been 'pinged' at 5kph over [73mph] which is a fair clip for a little Datsun to sustain.

OK, what's wrong with the auto trans? Is it faulty?

The diff ratio is the same for auto & manual so at highway cruise the RPM will be essentially the same since the torque converter will pretty much have locked up at those revs.

Auto's LOVE torque.
A15's mainly make torque, not horsepower.
The 1200's trans is a Jatco 3N71B, same as used in the more powerful L series powered models.

Here's a plan
1. Get crossmember from a 1974 or later Ute as these models used the same engine mounting positions as the A15 does. [different from early 1200 engine]
2. Install crossmember & engine. [it's almost a straight out bolt-in, ..... almost but not quite with alternator wiring & the engine mount bracket on the block on one side needing attention]

3. Fit rear wheels & tyres of increased diameter to try & increase the overall drive ratio. It's sort of like jacking up the diff ratio from 3.9 to 1 to perhaps 3.7 to 1
I recomend 205x60x13 on 6" rims as these fit nicely under my auto equiped 1200 coupe

Drive & enjoy. If still not satisfied then go with a twin SU type induction as these make good power & still have good vacuum. These Jatco trans' use a vacuum modulator to control the shift points so good vacuum is a must.

You will be amazed at just how much the driveability & performance will be improved while giving your left foot a good old rest.

Converting to a manual trans [you will need a 60 series] is a pain & in my view, will not yeild the results that you seek.

What the hell is a "stall converter"?
What he wrote was a "Hi-stall torque converter".

The stall speed of a torque converter is measured by placing the trans in 'D', then placing the left foot VERY firmly on the brake & after making sure that there is nobody in front, planting the right foot on the power pedal & flooring it.

Do this for ONLY AS LONG AS IT TAKES TO GET A MAXIMUM RPM READING from the tachometer that you have convenuently placed in clear view.

This exercise should take no more than about three seconds.
A standard torque converter will give a reading of somewhere around 1200 to 1500 revs for many vehicles.

A Hi-stall torque converter is a modified [or new built] unit that will allow a higher RPM to be reached under test conditions. These higher revs will give a modified engine a chance to develop some grunt before it is held back by the load of the vehicle.

They can also be a bit of a pain for normal driving if the stall speed is a bit high, like, ... above 2,500 rpm, but they launch like a demented third world refugee who just spotted a free hamburger.

Quote:
Because it doesn't use one.

The early, alloy housing H165's were the same, they used a fixed length sleve on the pinion with shims to control the bearing pre load.

For manufacturers this method was both costly & time cosuming to make, but for servicemen it was great.

It was much easier for manufacturers to just shove a single-use crushable sleeve in there & simply torque the pinion nut to specs then send it out the door, so for the iron H145/H165 this is just what they did.

For servicemen, replacing the seal [as per factory specs] is a major pain, but the factory didn't give a rats about that. It would be out of warranty by the time it needed a seal so why would they care.

The shape of the pinion shaft between the bearings is different between the two versions of the diff so the earlier sleeve can't be used on the later pinion but one can be manufactured if necessary to get around the problem.

It's a slower job to set it up in the first place, but the fixed length sleeve doesnt compress under high loadings & loose pre load on the pinion like the stock setup can.

Click on image for larger view.

If you are replacing the pinion oil seal in an iron housing H145 then be prepared for a little bit of work.

Here's the proper procedure.

Jack up car & remove both rear axles.
Uncouple driveshaft & remove differential.
Mount differential in suitable stand & remove hemisphere & crownwheel assembly
Remove drive flange & extract pinion.
After cleaning housing, replace seal.
Fit new colapsable pinion pre load spacer & refit pinion.
Refit all other parts.
Check & adjust as necessary pinion depth of mesh & preload as well as pinion to crownwheel free play.
Correct as necessary.
Using new gasket, refit differential to rear axle housing.
Re-install axles & refit drive shaft.
refill diff with oil
Run car in gear on jackstands to check that all is well.

Lower car to ground & return it to service.

For alloy housing H145

1. Place car on jacks or hoist.
2. Remove drive shaft & drive flange.
3. replace seal.
4. reverse steps 2 & 1

I drove through Goulburn on Easter Friday, & the following day I spent 30 minutes driving around the city without seeing a single solitary Datsun car.

It was just before sunset & several laps along the main street as well as hiting the showground & both MacDonalds produced nothing.
I just drove around to all of the places that I figured that people might go to get fed, or to camp for the night, ......... nothing.

Did someone call off the Datnats or what?

Quote:Correction

You CAN use the early [front distributor] head on the later cylinder block as the oil feed to the rockers is pumped directly up the correct head bolt hole in the cylinder head.

You can NOT use the later head on the early block because the early block feeds the rocker oil to a small vertical drilling at the side of the cylinder head gasket face. The cylinder head needs a corresponding drilling that feeds the oil across to the same cylinder head bolt hole as the later engines.

Since the newer heads do not have the drillings necessary to pick up the early engines oil feed, the rockers will not get any oil at all with predictable results.

Perhaps you could re-read your post as if you were a complete stranger to see it as others see it.

I have no idea of what it is that you want or need.