starter motor for slant six
First off: answer to the original question is YES, the 318 starter will go on the 225 just fine. They are one and the same in '71.
Secondly: "Remanufactured" starters are junk. They are unreliable and they sound like hell. If you want a brand-new Chrysler starter you can get one (a real one, not a "100% new!" copycat piece of junk from China) from Old Car Parts Northwest.
Almost all '62-'87 RWD Chrysler products built in North America used a Chrysler-built gear reduction starter. The exceptions are as follows:
-'66-'71 Hemi/4-speed cars used Chrysler direct-drive solenoid shift starter
-Slant-6 vehicles with 11" clutch (truck, taxi, police) used Chrysler direct-drive solenoid shift starter
-'63-'66 Canadian-built vehicles used Prestolite ("Auto Lite") direct-drive Bendix drive starter
The direct-drive starters don't interchange with the gear-reduction units because the drive pinion on the DD starter has 9 teeth and 25mm diameter, while the drive pinion on the GR starter has 10 teeth and 33mm diameter.
All the '62-'87 gear reduction starters are interchangeable, but they are not all alike. There is a wide range of cranking speed and torque. All the gear-reduction starters were electrically identical from '62 through early '73 (p/ns 2095 150, 2875 560, 3656 650) whether they went on a 225 or a 440 or anything in between, except all '63 engines and '64-'69 170 slant-6s got a starter with 4 series coils instead of 3 series/1 shunt. The 4-series starter (p/n 2098 500) has about 20% faster cranking speed than the 3-series/1-shunt unit. Rated power of both units is 1.3hp, though the 4-series unit is probably closer to 1.4hp.
In late '73 all engines got a 1.5hp version of this starter with 4 larger-than-'63 series coils (p/n 3656 575, 3755 900, 4091 975 and a few others). Cranking speed went up again.
All of the above starters have 3.75:1 gear reduction.
In '74 the large-frame 1.8hp version of the starter, with 2:1 gear reduction and much higher cranking speed was released on 360, 400, and 440 engines (p/n 3755 250, 4091 950, and a few others). From '74 through '87, the small-frame and large-frame starters were electrically unchanged and were used on various engine sizes depending on year, assembly plant, emissions package, and phase of the moon.
All the above starters interchangeable as long as you've got the space for the ~½" longer large-frame starter compared to the small-frame unit. Only a few of us really geek out on the differences among them.
The first version of the Nippondenso-made mini starter was used on Mopars in late '88. Subsequent versions of it were made smaller and more powerful. It is a very well-designed starter, and as long as you get the real Nippondenso (later "Denso") unit and not the Chinese copycat junk, it is a very well-built and durable starter. Its only drawback is that your old Mopar will no longer sound like an old Mopar when you are cranking it -- decide for yourself if that's a dealbreaker. The one to get is from any '89-'01 RWD 3.9, 5.2, or 5.9 engine (M-body cars + trucks/vans). On the rare occasion they fail to crank, it's almost always fixed by replacing the solenoid contacts, which is an easy benchtop job. Sometimes the original hookup locations are inconvenient. There are multiple different connectors available, though, to solve that issue. See here for connection options and see here for solenoid contact info.
Any more questions about Chrysler starters…?
First off: answer to the original question is YES, the 318 starter will go on the 225 just fine. They are one and the same in '71.
Secondly: "Remanufactured" starters are junk. They are unreliable and they sound like hell. If you want a brand-new Chrysler starter you can get one (a real one, not a "100% new!" copycat piece of junk from China) from Old Car Parts Northwest.
Almost all '62-'87 RWD Chrysler products built in North America used a Chrysler-built gear reduction starter. The exceptions are as follows:
-'66-'71 Hemi/4-speed cars used Chrysler direct-drive solenoid shift starter
-Slant-6 vehicles with 11" clutch (truck, taxi, police) used Chrysler direct-drive solenoid shift starter
-'63-'66 Canadian-built vehicles used Prestolite ("Auto Lite") direct-drive Bendix drive starter
The direct-drive starters don't interchange with the gear-reduction units because the drive pinion on the DD starter has 9 teeth and 25mm diameter, while the drive pinion on the GR starter has 10 teeth and 33mm diameter.
All the '62-'87 gear reduction starters are interchangeable, but they are not all alike. There is a wide range of cranking speed and torque. All the gear-reduction starters were electrically identical from '62 through early '73 (p/ns 2095 150, 2875 560, 3656 650) whether they went on a 225 or a 440 or anything in between, except all '63 engines and '64-'69 170 slant-6s got a starter with 4 series coils instead of 3 series/1 shunt. The 4-series starter (p/n 2098 500) has about 20% faster cranking speed than the 3-series/1-shunt unit. Rated power of both units is 1.3hp, though the 4-series unit is probably closer to 1.4hp.
In late '73 all engines got a 1.5hp version of this starter with 4 larger-than-'63 series coils (p/n 3656 575, 3755 900, 4091 975 and a few others). Cranking speed went up again.
All of the above starters have 3.75:1 gear reduction.
In '74 the large-frame 1.8hp version of the starter, with 2:1 gear reduction and much higher cranking speed was released on 360, 400, and 440 engines (p/n 3755 250, 4091 950, and a few others). From '74 through '87, the small-frame and large-frame starters were electrically unchanged and were used on various engine sizes depending on year, assembly plant, emissions package, and phase of the moon.
All the above starters interchangeable as long as you've got the space for the ~½" longer large-frame starter compared to the small-frame unit. Only a few of us really geek out on the differences among them.
The first version of the Nippondenso-made mini starter was used on Mopars in late '88. Subsequent versions of it were made smaller and more powerful. It is a very well-designed starter, and as long as you get the real Nippondenso (later "Denso") unit and not the Chinese copycat junk, it is a very well-built and durable starter. Its only drawback is that your old Mopar will no longer sound like an old Mopar when you are cranking it -- decide for yourself if that's a dealbreaker. The one to get is from any '89-'01 RWD 3.9, 5.2, or 5.9 engine (M-body cars + trucks/vans). On the rare occasion they fail to crank, it's almost always fixed by replacing the solenoid contacts, which is an easy benchtop job. Sometimes the original hookup locations are inconvenient. There are multiple different connectors available, though, to solve that issue. See here for connection options and see here for solenoid contact info.
Any more questions about Chrysler starters…?