Quote:
Originally Posted by Formulabruce
I do Not knock these ratios, and I own a very early 1971 2.73 rear, and a late 76 2.41 .
What OPH said was pretty much true though. A 2 series ( 8.75 ring gear) "Safe-T-Track" or "Posi"carrier for a 68-70 12 Bolt Chevy /Pontiac is a rare piece. Not reproduced. The open ones are around though.
In a 10 bolt ( '71 -81 for this conversation) you can use a 3 series carrier for a 2.73
gear ( have built a few myself), but NOT for a 2.56 or 2.41 . Also New carriers for these 8.5 rears are all over and some are inexpensive and have carbon fiber clutches vs steel.
If you want to use your TH400 and cruising and economy is paramount,
Call Franks Pontiac and grab a 2.41 Posi from a Firebird. With 15 inch 25 inch tall tires youll be at around 2500 at 72 mph ( a mere guess without any wind resistance). There are calculators to try online.
I happen to like Overdrive, and this is a pic of a car of mine with 3.42 gears,
26 inch tall tires ( 225/70/15 -- same as in 1979) and .67 OD .. taken on I-95 --- Th2004R transmission
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I like those numbers . You guys are good. It is simply difficult to get that with a turbo 400 but with the new Trans I can do that. Hmm what about the shifter is it the same? Or did you put the 82 through 92 shifter in it. And is a 700 r4 stronger than the 200 r4. Happy new year. Doing this is going to side track my stock build but those cruise numbers are very good. I bet it's good gas milage and less wear on engine. Do you need a computer box with that tranny. I'm very curious.