t5 5spd and 3.89 gears

I'll bet it is perfect on the hi-way now...

 

I am soliciting bids for a 5 speed conversion kit for my 65. So far, I have talked to two vendors, one using the T-5 and the other using the Tremec. (They machine the case so the transmission clears the floor). Are you using the .62 or .82 fifth gear? I have pretty much decided on the 2.95 low. Still undecided about fifth gear. My car has 3.89’s, the .62 firth make it 2.41. If I go with the .8 fifth, that’ brings final to 3.11. My car has an extremely radical camshaft, it doesn’t like to run on the highway under 2000.

 

Bill.
I can only use my own experience for advice. I used a T5 from an 80's HO mustang. There is an adapter plate between the tranny and the bell-housing to make the output shaft length work and so they both bolt together. The shifter is the four speed shifter that came with my car. (cut off and bolted to the T5 stub. It comes right through the hole in the tranny tunnel (perfect) the speedo gear and cable from the original car went right into the T5, The clutch linkage and brackets are all original to the 65 car. The x member is fabricated part. Very clean and non destructive swap. No part of the car had to be cut or bent. My car has 3.89 gears, 215 X 15 tires 55 mph is 2000 rpm ..very nice. If I'm stomping on it at 55 It does OK. If I am STOMPING on it at 55 I put it back into 4th gear. In a drag race I am in 3rd still at the finish ( I don't know which OD ratio I have ) When I did the swap I don't recall knowing that there were two possibilities. My cam shaft is one ofm those C7 Le Mans jobs .. It may not be a hairy as the one you have but it is still pretty lumpy

I heard that the Tremec tranny needs to use a cable clutch.. I have an X pipe crossover... between that, the hand brake cable and the the driveshaft
yoke thing are pretty tight in that spot but it all works good..(with the T5).. I don't know about the Tremec
jimbo

 

SFM5S155 had one of those camshafts, it was an excellent working stick. There is a T-5 with a .73 fifth gear and a 2.95 low. I most likely will go with that one. Stay Tuned.
Thanks
Bill

 

Bill,
Sounds like the right 5th gear. A friend of mine had the LeMans cam, 4.11 gears and the T5Z with the .6 5th and 5th was usable at 70 and above.

 

I am trying to avoid going from one extreme;

3250 RPM at 60 MPH

to another:
2000 RPM at 60 MPH with a .62 fifth. I don't think this would work given the camshaft and cubic inches.

2400 RPM at 60 MPH with a .73 fifth. This one looks like a solution.

 

What times are you running? My 66 fastback has a 9 inch with 3.89's and a t-5. I am trying to decided if I want to shift into fifth or stay in 4th at the end of the quarter mile. I usually run high 12's at around 108 mph.

 

After reading this forum I decided to post my own experience with my 66 Fastback. Recently purchased a Keisler Perfect Fit with the 2.87 first, 1.89, 1.28, 1.0, .64 fifth. Project started with a replacement Flaming River steering box, decided that I need to recoat my headers, then decided if I have gone this far might as well replace the tranny. Well with a 351 Windsor swap done a while ago I have 5 hrs invested in installing the passenger side headers. Still cannot get driver side in. May need to get a cherry picker or try somehow moving the steering box to get the header in. Did I mention that I am doing this with four jack stands. Somebody shoot me

Looking forward to testing the tranny, using 3.55 rear gears. May need to bump it up to a 3:89. Seems like others are stating that they do not need to use the 5th gear until 75+mph. I would like to keep up with the new Vettes without blowing the motor.

 

I was told that the Tremec trans could be modified to fit without cutting the floor, but the driveline angle was all wrong. Did you run into this?

 

I was told that the Tremec trans could be modified to fit without cutting the floor, but the driveline angle was all wrong. Did you run into this?


Go to Keisler Perfect Fits website. The reason I chose them over others is that they include everything needed to a full tranny swap. The only thing that I have had to cut was a "rib" underneath the tranny tunnel. A little less than a dollar bill size. No realignment of shifter at all. Everything fits perfectly. Speaking with a sales rep he mentioned that they supply their trannys to Unique Performance, makers of the Eleanor Shelbys and GT 350sr.

Feel free to ask me any more questions. I would be happy to share my experience with the setup.