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tall final drive ratio

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    tall final drive ratio

    This is mostly a question about final drive ratio in an automatic tranny. Here's why I ask:

    Our best car (1990, 82k) got smushed. It ran absolutely like new. Does a BG powerplant (SOHC, auto) have any use in today's world? I see hardly any 1st gen cars anymore. For several months I've been thinking to save the drivetrain in case our "old" faithful (1994, 235k) ever needs a transplant... but in truth, the "old" one runs just fine, I just rebuilt the entire head a couple of years ago so it's unlikely to puke a head gasket any time soon... and its body will probably die first. Tearing apart a donor is a lot of work for a "just in case I need it" situation.

    Regarding transplants, you guys don't mess with anything less than DOHC, I know. Preferably with 2-3 turbos. {grin} Don't get me wrong, I know the hod rod territory well. But for just getting around, the SOHC does everything I need. Besides, CA smog laws are pretty strict, so stuffing this into anything other than a BG would be a hassle.

    For those few of us looking for mpg... to me, the most intriguing feature is the 3.476 final gear, the tallest of any Protege from 1990-2003. In looking for a replacement Protege, 2002-03 is about the oldest being offered... AND a common complaint is the highway rpm from a 3.904 gear. Hmmm... Would I be able to swap the ring and pinion from a F4A-EL into a FN4A-EL? Analysis of the exploded view shows they're incredibly similar.

    On the other hand, the subsequent FS5A-EL *does* have a 3.458 final drive available, and is an incredibly close cousin to the FN4A-EL. So if I ever really wanted to swap a tall gear into, say, a P5, I'm betting that would be much easier to use 2006+ parts than 1990 parts. I've seen several references to 5-spd changes, but has anyone done any gear swapping in an autotragic?

    I hate to send a fantastic drivetrain to the crusher, but unless I can come up with a current or future use for it...

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