1963-69 starter question, and it's a good one...

Good evening:

Let's see if anyone knows or pretends to know the answer to a question I will include near the end of this post. First, some factual information-

At least as far back as 1962 and lasting through most of the 1969 model year, Chrysler equipped vehicles that had automatic transmissions and manual transmissions using small-diameter clutches with gear-reduction starters. Large-diameter clutches got a direct-drive starter. What most people may not know is that there were two different starters used depending on whether the vehicle had a 170 cid Slant Six.

Part # 2095150 is the very common unit used on everything except a 170 Slant. 225 Slant, 318, 361, 383 413, 426 Hemi..it all got the 2095150. Part # 2098500 is the unit used on the 170 Slant only, 1963-69. Someone said in '63 everything used this starter, but per the parts book that appears to be incorrect.

Here's where it gets interesting...

2095150 is a 3-series/1-shunt starter motor. That means it has 4 field coils per se, with 3 coils in series and 1 used as a shunt. A shunt coil is used primarily to limit the speed of an electric motor to prevent damage from overspeeding. Someone with more electrical knowledge than I can explain it better. I think this design is called a compound motor.

2098500 is a 4-series motor with no shunt. It's rated speed is 1000 rpm faster than the 2095150 starter and that's accurate...I have one.

In practice, the 2095150 is a slower-turning, quieter starter since it does not have the overrun even if you hold the key. The downside is that if you have a heat-soaked engine or a very cold engine, you are leaning on the key a long time. The 2098500 as i stated turns the engine much faster, with noticeable overrun. The upside is a faster-starting engine. That unit spins almost as fast as one of the later 3755900 starters.

The question: Why use a faster-spinning starter on a smaller displacement engine?