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Oldsguy · February 23rd, 2006, 07:27 AM

Well, I'll just say this, I think there are more than one type of GM two speed automatics and yours MAY not be the powerglide. If someone bolted up a 260 in your f85 I can't see them using a powerglide because they are desirable for dragracing as you mentioned. A drawback of using a two-speed on the street is poorer fuel economy and drive-ability, you may find the engine turning up too high before the shift, not to say it is too high for engine durability but just may be irritatingly too high for everyday use. As was mentioned earlier a TH350 or TH400 would be good depending on what engine you decide on. The muncie would require that you set up the car for manual operation with a clutch (hanging the clutch pedal, etc.)

Personally, I recommend you find an engine/tranny combo from someplace and drop them in together. If you can find a running set from say a wrecked car, then you are two steps ahead. A bone stock 455 from an early seventies B body has GOBBS of torque that would roast the tires in that little f85. If the engine is in good shape already you can spend your money on other stuff but if you are prepared to spend lots of money anyway then the 455 will respond very well to improvements. Also, depending on the length of the tranny tailshaft you may have to shorten the driveshaft to fit. However you go, getting an engine/tranny set together would put you ahead....

Good luck.

February 23rd, 2006, 07:27 AM	#15 (permalink)
Oldsguy Hot Rodder at heart Administrator Join Date: May 2004 Location: Lees Summit MO Posts: 5,360	Well, I'll just say this, I think there are more than one type of GM two speed automatics and yours MAY not be the powerglide. If someone bolted up a 260 in your f85 I can't see them using a powerglide because they are desirable for dragracing as you mentioned. A drawback of using a two-speed on the street is poorer fuel economy and drive-ability, you may find the engine turning up too high before the shift, not to say it is too high for engine durability but just may be irritatingly too high for everyday use. As was mentioned earlier a TH350 or TH400 would be good depending on what engine you decide on. The muncie would require that you set up the car for manual operation with a clutch (hanging the clutch pedal, etc.) Personally, I recommend you find an engine/tranny combo from someplace and drop them in together. If you can find a running set from say a wrecked car, then you are two steps ahead. A bone stock 455 from an early seventies B body has GOBBS of torque that would roast the tires in that little f85. If the engine is in good shape already you can spend your money on other stuff but if you are prepared to spend lots of money anyway then the 455 will respond very well to improvements. Also, depending on the length of the tranny tailshaft you may have to shorten the driveshaft to fit. However you go, getting an engine/tranny set together would put you ahead.... Good luck. __________________ Dan '77 Cutlass Supreme '46 2 door "The rocket 455.....it's a sledgehammer approach to a thumbtack world" LuxBlue of HAMB.