rear end gear recomendations

mikesfastss

mikesfastss

Club Member
78 Monte Carlo BBC 468 turbo 400 trans with 4000 stall gonna be street driven and might make a few track rentals car has full interior and makes 500 ish h.p. and about same torque.and ideas I've got an 8.5 from a grand national I'm gonna use
 
I'd keep

mikesfastss said:
78 Monte Carlo BBC 468 turbo 400 trans with 4000 stall gonna be street driven and might make a few track rentals car has full interior and makes 500 ish h.p. and about same torque.and ideas I've got an 8.5 from a grand national I'm gonna use
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Id keep the 3.42 that's in it.
 
What size tire?? That matters.

If a 26" tire I'd do 3.42-3.55

If a 28" tire I'd do 3.55-3.73

This should cruise at 65 mph at 3000 rpm. My 28"/3.73 combo does exactly 63 mph at 3000 rpm.
 
I think a 3.73 with a 28" tire may keep the converter slipping depending on how tight it is...for me i'd go 4.10 28" tire. I would definately not go any lower than a 3.73.
 
Billydroveit said:
I think a 3.73 with a 28" tire may keep the converter slipping depending on how tight it is...for me i'd go 4.10 28" tire. I would definately not go any lower than a 3.73.
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Agreed. 4k is a pretty high stall. Depends on the design of converter. On another note 63mph @ 3000 rpm will feel like its a high rpm with a BB Chevy. A little uncomfortable for cruising.
Tire height x pie divided by 12= x
5280 divided by x = y
y x gear ratio = rpm @ 60 mph.
 
Ya I bought the car with the setup in of I was thinking about changing the stall maybe 3400 of so ,guess ill do the rear end and drive it first then decide on that
 
Just keep in mind if you start with a 4.10 and feel comfortable going lower to a 3.73 it wil cause the converter to slip a little more with the 3.73. But if you don't plan on freeway driving it, the 4.10 will probly be perfect and alot of fun
 
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