Depends on what you are talking about. If you are talking about an '87 and earlier model, 9 times out of 10, the part store's idea of a "high torque starter" is just a normal starter with a higher price tag. Once there was a real high torque starter that was a physically larger version of the typical Mopar starter, but I doubt anyone even bothers to make a real one anymore. In any case, no, a high torque stock type Mopar starter would not be worth it.
Now if you are talking about the '88 and later "mini" Nippon starter, yes, they are most definitely worth it. They are smaller, which makes install easier and has more clearance for headers, they spin faster and draw less amps and, in my experience, they seem to handle heat a lot better than the old Mopar starters. An easy upgrade that you will notice every time you start your engine.
It's a direct replacement. I've used the mini starter on big blocks and small blocks and I know of a crate 426 Hemi using one. The only Mopar starter I think it won't replace is the old oddball Hemi 4 speed starter.
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