1989 GT - what rear gear should I use with my 3 speed tranny?

ccdguy · 11-02-2009, 12:29 PM

Hey guys... I just bought a project, 1989GT with a 306 stroker. It is in pretty good shape for it's age. My question is this, the tranny is a C4 - 3 speed with manual reverse lockout and transbrake. Rear end is an 8.8" with 3.73. Needless to say, at 60mph, I'm at 3K rpms. Not good.... I can either swap out to a different transmission (expensive), or my choice, lower the gears in the back. The tires are 245 45 17", so my choices are either 3.08 or better yet 2.73 in tha back... With the current 3 speed tranny, tire/rim size and say 2.73 gears in the back, I'd be able to get it on the highway for some cruising with my club at 75mph, and comfortable 2500rpm.... Do you think that this is the way I should go to make this car a better cruiser, rather than a stop light to stop light rocket...???
Your comments would be appreciated.. Thanks in advance.

Martin

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nba1341 · 11-02-2009, 03:12 PM

2.73 are slow as **** you will regret putting them in

3.27 gears would get you at a little over 3200rpm at 75mph

3.08 would get you right at 3000rpm at 75mph

TrimDrip · 11-02-2009, 03:40 PM

if you are not racing, why not just get a 5-speed?

ccdguy · 11-02-2009, 03:51 PM

Why not a T5 tranny??? Costs.... Baby on the way... Stuff like that to consider... I'd love too, but we're talking at least 2 grand for tranny and install.... Gear solution? Few hundered bucks? But you know what... with the engine making 300rwhp+ with load of TQ, the three speed with 2.73's would not be that bad... Can't be any worse that a bone stock 89 GT 302.... Or my current DD, 05 Mustang 4.0L with stock 3.31's in the back. Could always look to see if I can throw on taller tires on the back rims... Instead of 45s, maybe 50 or 55's. That would lower the rpm at highway speed, and might allow me to go with 3.08s??? Just exploring all options.... Thanks for your input.....

TrimDrip · 11-02-2009, 04:09 PM

i forget you are not from here and everybody wants like 300% mark-up on things

a gear install for you is a 5-speed swap in Alabama

Or you could just drive it down here and let my buddy hook you up for a few less than a grand. You will need pedals and a clutch cable.

mjr46 · 11-02-2009, 06:30 PM

I think you should read forum rules on where to post such threads, this is the tech section, not opinion section, gen disc is for such.

ccdguy · 11-02-2009, 08:05 PM

Quote:

Originally Posted by mjr46

I think you should read forum rules on where to post such threads, this is the tech section, not opinion section, gen disc is for such.

Ahhh, K..... Thought it was a technical question from my point of view, but I do agree it asked for opinions.... Aren't most technical posts asked on these forums, to be answered, and opinions to be shared... But whateva'.... I stand corrected. Thank you to those whom I have not "offended", and answered my post.... Off to reading the forum rules for the rest of the night.......

AntiRiceRacing · 11-02-2009, 08:30 PM

If you plan on "cruising" the c4 is not for you.

5.0kid · 11-02-2009, 09:06 PM

what gears do you have now again 3.73? how bout a bigger tire im running a 28x10.5 out back with my 3.73's n im getting about 3100 at 70, though ive only been on the freeway twice since i put my c4 in. lol id go with a t-5 you can get them dirt cheap. Hell you want one? I got one that need a rebuild ill sell it to ya for 75 obo + shipping