Tremec TKO II w/ 0.82 OD and 3.73 rear end... Mistake?

[Treachery]

Hi all.

I just had a Tremec 3550 TKO II (0.82 overdrive) installed in my '93 GT with a Vortech SQ-Trim blower and a 3.73 rear end.

The Tremec is great and i love it BUT my Mustang rev's higher on 5th gear than i would like it to. I knew that a 0.82 overdrive would push up the RPM's on 5th gear but didn't realize it would push it up as much as it does!

My observation:

Pros: less shifting from 5th to 4th; power is really "on demand" when on 5th especially with the Vortech- more RPM's.. more boost.. etc.

Cons: GAS! My gas guzzler guzzles more gas! 80 miles=1/2 tank gone (not my main concern however); RPM's too high- very difficult to cruise. LOSS OF HIGH END! My RPM guage matches my speedometer! @ 120mph the car is almost at the red and is working very hard.

Solution? - Drop the rear end from 3.73 to 3.55 ? Would acceleration be hurt thus my 1/4 mile time suffers?

For those who have a TKO-II with 3.73's.. Should i stay with 3.73's or go 3.55? I personally want to stay with 3.73 but the Cons out weighs the Pros.

[Dark_5.0]

You should never hit 5th at the track unless you have a 6 speed.

What is your trap speed in the 1/4 and are you running 26 or 28 inch rear tires.

[Treachery]

Never made it to the track.. The track is a good 70 miles from where i live and "race night" is on a Wednesday.. A good 150 miles from work.

I never rode in a Mustang with 3.55 gears much less one with a 0.82 5th gear.. I figure the RPM's would drop when on 5th.. but how would acceleration be affected?

Thanks.

[~The Jester~]

Keep in mind that on a 4 speed + overdrive (which is what you have) that 4th is direct. Going with your .82 OD ratio, 4th is 1.00!! So there really isn't alot of difference. I'm running a TKO with .65 OD and it's just awesome. Actually have 4.30's in the car as well, shimmy on down into overdrive for the freeway. NICE!

Possible solutions for you. Keep in mind that everything is a compromise. What you gain on top end (or Revs) you'll loose on the bottom. I sorta like the "ass dyno", which is why I have such a steep gear. You can't touch my dashboard in 3rd gear. hehehehehe

What size tire are you running? Taller tire will help you out a bit. Dropping down to 3.55 will help a bit. Installing the OD cluster from another tranny with the .65 will help, and not cost you on the bottom end. Of course, the win/win situation is the most expensive and the most difficult. Hope this helps!

[Treachery]

The tires i'm running are either P245/75R16 or P245/70R16.. don't know off-hand.

You mentioned installing the OD cluster from a tranny with .65.. This may be what i need. Please elaborate.