Kloppy80

Since considering changing engines, the issue of rear end ratios have come up. Can anyone give me suggestions and how can I know what I already have in my 80? At 70 MPH, I am running about 3000 RPM!
Thanks:
Kloppy80 :D

Smokehouse69

If your tires are 26" tall, then you have a 3.32 rearend ratio. You must have a 4-speed, since I don't think that rearend was available in an automatic in 1980.
Have you considered a 6-speed either a Richmond Gears or a T-56? With a .62 overdrive you'd only be turning 1800-1900 rpms at 70mph! GWhite75 just finished a T-56 in his car, and said it wasn't all that tough of an upgrade. I think it cost him under $2100.00 (I could be wrong, so check with him) for the tranny and the shipping from New York to Texas.
He reused all the standard 4-speed pedal and clutch mechanism.



[Modified by Smokehouse69, 4:05 PM 1/25/2002]

Kloppy80

I have an automatic! Someone thought that I might have a 3.07 in it. If I'm not mistaken, I was told that a 3.73 was recomended if I was going to a 383 Stroker 450 HP. Does this seem reasonable? :confused:

DeenHylton

What's your driving style? Are you going to run a higher stall converter? If your mainly into street/highway crusing I'd stick with the 3.55's and run a mild stall (2,200-2,400 RPM stall). Just my 2 cents worth...Deen

Kloppy80

Deen:
Yeah, I'll strictly be running street! The 3.55 seems like a reasonable compremise though. You recommended a 2,200-2,400 RPM stall. I'm still a novice, so help me understand what a stall is. Thanks! :confused:

DeenHylton

Stall is the amount of RPM you can achieve by having the tranny in drive, one foot firmally holding the brake pedal and the other foot pushing on the gas. Your stock stall converter will probably let your engine climb to 1.500 RPM before it tries to move the car...a higher stall converter lets the engine RPM higher up (closer to its power range) to help accelerate the car faster. If your building a 450 HP 383, it's going to have a more aggressive cam to achieve the 450 HP figure. The cam will move the power band up higher in engine RPM's, to take full advantage of the power band of this engine you will need to raise your stall accordingly. As an example, if all things are equal you would see .3-.4 tenths different in the quarter mile times running a higher stall torque converter over a stock one. Since your going to have to pull the engine/tranny anyway to drop in the 383, you might as well install a higher stall torque converter at the same time. B&M's "Holeshot 2400" or TCI's "Break-A-Way" would be in the ball park of what you'd need...they are priced around $200-230 from Jeg's or Summit. Deen

Ganey

You want the converter & gears to match the engine. A 383 can stall at 2000 w/ stock converter. You need to post engine specs. esp. cam.

:cool: